Rename _MainDepthTexture to _CameraDepthTexture (For builtin compatibility)

Old code require to use _CameraDepthTexture name, we have change it to
MainDepthTexture  a while ago because of bug due to usage of
GetTemporaryRT, as we don't use GetTemporaryRT anymore we can now come
back to the original name

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Debug/DebugViewMaterialGBuffer.shader

             float4 Frag(Varyings input) : SV_Target
             {
                 // input.positionCS is SV_Position
-                float depth = LOAD_TEXTURE2D(_MainDepthTexture, input.positionCS.xy).x;
+                float depth = LOAD_TEXTURE2D(_CameraDepthTexture, input.positionCS.xy).x;
                 PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
 
                 BSDFData bsdfData;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Debug/DebugViewTiles.shader

             float4 Frag(Varyings input) : SV_Target
             {
                 // positionCS is SV_Position
-                float depth = LOAD_TEXTURE2D(_MainDepthTexture, input.positionCS.xy).x;
+                float depth = LOAD_TEXTURE2D(_CameraDepthTexture, input.positionCS.xy).x;
                 PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V, uint2(input.positionCS.xy) / GetTileSize());
 
                 int2 pixelCoord = posInput.positionSS.xy;
                 int maxLights = 32;
                 if (tileCoord.y < LIGHTCATEGORY_COUNT && tileCoord.x < maxLights + 3)
                 {
-                    float depthMouse = LOAD_TEXTURE2D(_MainDepthTexture, _MousePixelCoord.xy).x;
+                    float depthMouse = LOAD_TEXTURE2D(_CameraDepthTexture, _MousePixelCoord.xy).x;
                     PositionInputs mousePosInput = GetPositionInput(_MousePixelCoord.xy, _ScreenSize.zw, depthMouse, UNITY_MATRIX_I_VP, UNITY_MATRIX_V, mouseTileCoord);
 
                     uint category = (LIGHTCATEGORY_COUNT - 1) - tileCoord.y;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/Deferred.shader

                 // This need to stay in sync with deferred.compute
 
                 // input.positionCS is SV_Position
-                float depth = LOAD_TEXTURE2D(_MainDepthTexture, input.positionCS.xy).x;
+                float depth = LOAD_TEXTURE2D(_CameraDepthTexture, input.positionCS.xy).x;
                 PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V, uint2(input.positionCS.xy) / GetTileSize());
                 float3 V = GetWorldSpaceNormalizeViewDir(posInput.positionWS);
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/DeferredDirectionalShadow.compute

 
 #include "CoreRP/ShaderLibrary/Common.hlsl"
 #include "../ShaderVariables.hlsl"
-#include "Lighting.hlsl" 
+#include "Lighting.hlsl"
 
 #pragma only_renderers d3d11 ps4 xboxone vulkan metal switch
 
 	float2 startUV = rayStartCS.xy * 0.5f + 0.5f;
 	startUV.y = 1.0 - startUV.y;
 
-	// Pixel to light ray in 
+	// Pixel to light ray in
 	float2 rayUV = rayCS.xy * 0.5f;
 	rayUV.y = -rayUV.y;
 
 		float raySampleDepth = startDepth + rayDepth * sampleStep;
 
 		// Depth buffer depth for this sample
-		float sampleDepth = SAMPLE_TEXTURE2D_LOD(_MainDepthTexture, sampler_MainDepthTexture, sampleUV, 0.0).x;
+		float sampleDepth = LOAD_TEXTURE2D(_CameraDepthTexture, sampleUV).x;
 
 		bool Hit = false;
 		float depthDiff = sampleDepth - raySampleDepth;
 	uint2 pixelCoord = groupId * DEFERRED_SHADOW_TILE_SIZE + groupThreadId;
 	uint2 tileCoord = groupId;
 
-	float depth = LOAD_TEXTURE2D(_MainDepthTexture, pixelCoord.xy).x;
+	float depth = LOAD_TEXTURE2D(_CameraDepthTexture, pixelCoord.xy).x;
 
 	if (depth == UNITY_RAW_FAR_CLIP_VALUE)
 		return;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/LightLoop/Deferred.compute

 
     // This need to stay in sync with deferred.shader
 
-    float depth = LOAD_TEXTURE2D(_MainDepthTexture, pixelCoord.xy).x;
+    float depth = LOAD_TEXTURE2D(_CameraDepthTexture, pixelCoord.xy).x;
     PositionInputs posInput = GetPositionInput(pixelCoord.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V, tileCoord);
 
     // For indirect case: we can still overlap inside a tile with the sky/background, reject it

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScattering.shader

                 // Reconstruct the view-space position.
                 float2 centerPosSS = posInput.positionNDC;
                 float2 cornerPosSS = centerPosSS + 0.5 * _ScreenSize.zw;
-                float  centerDepth = LOAD_TEXTURE2D(_MainDepthTexture, centerPosition).r;
+                float  centerDepth = LOAD_TEXTURE2D(_CameraDepthTexture, centerPosition).r;
                 float3 centerPosVS = ComputeViewSpacePosition(centerPosSS, centerDepth, UNITY_MATRIX_I_P);
                 float3 cornerPosVS = ComputeViewSpacePosition(cornerPosSS, centerDepth, UNITY_MATRIX_I_P);
 
                         // Apply bilateral weighting.
                         // Ref #1: Skin Rendering by Pseudo–Separable Cross Bilateral Filtering.
                         // Ref #2: Separable SSS, Supplementary Materials, Section E.
-                        float rawDepth    = LOAD_TEXTURE2D(_MainDepthTexture, samplePosition).r;
+                        float rawDepth    = LOAD_TEXTURE2D(_CameraDepthTexture, samplePosition).r;
                         float sampleDepth = LinearEyeDepth(rawDepth, _ZBufferParams);
                         float zDistance   = centimPerUnit * sampleDepth - (centimPerUnit * centerPosVS.z);
                         sampleWeight     *= exp(-zDistance * zDistance * halfRcpVariance);

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/CameraMotionVectors.shader

 
         float4 Frag(Varyings input) : SV_Target
         {
-            float depth = LOAD_TEXTURE2D(_MainDepthTexture, input.positionCS.xy).x;
-        
+            float depth = LOAD_TEXTURE2D(_CameraDepthTexture, input.positionCS.xy).x;
+
             PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
 
             float4 worldPos = float4(posInput.positionWS, 1.0);
     SubShader
     {
         Tags{ "RenderPipeline" = "HDRenderPipeline" }
-        
+
         Pass
         {
             // We will perform camera motion velocity only where there is no object velocity

ScriptableRenderPipeline/HDRenderPipeline/HDRP/ShaderPass/ShaderPassDBuffer.hlsl

 {
     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
-    float depth = LOAD_TEXTURE2D(_MainDepthTexture, input.positionSS.xy).x;
+    float depth = LOAD_TEXTURE2D(_CameraDepthTexture, input.positionSS.xy).x;
     PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
 
     // Transform from world space to decal space (DS) to clip the decal.

ScriptableRenderPipeline/HDRenderPipeline/HDRP/ShaderVariables.hlsl

 
 // ----------------------------------------------------------------------------
 
-TEXTURE2D(_MainDepthTexture);
-SAMPLER(sampler_MainDepthTexture);
+TEXTURE2D(_CameraDepthTexture);
 
 // Main lightmap
 TEXTURE2D(unity_Lightmap);

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Sky/OpaqueAtmosphericScattering.shader

 
             float4 Frag(Varyings input) : SV_Target
             {
-                float depth = LOAD_TEXTURE2D(_MainDepthTexture, input.positionCS.xy).x;
+                float depth = LOAD_TEXTURE2D(_CameraDepthTexture, input.positionCS.xy).x;
                 PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
 
                 if (depth == UNITY_RAW_FAR_CLIP_VALUE)