HDRenderPipeline: use width instead of height for depth and color pyramid for consistency

+ use sRGB for SSSBuffer in forward only

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

             using (new ProfilingSample(cmd, "Gaussian Pyramid Color", GetSampler(CustomSamplerId.GaussianPyramidColor)))
             {
                 var colorPyramidDesc = m_GaussianPyramidColorBufferDesc;
-                var pyramidSideSize = colorPyramidDesc.height;
+                var pyramidSideSize = colorPyramidDesc.width;
 
                 // The gaussian pyramid compute works in blocks of 8x8 so make sure the last lod has a
                 // minimum size of 8x8
             using (new ProfilingSample(cmd, "Pyramid Depth", GetSampler(CustomSamplerId.PyramidDepth)))
             {
                 var depthPyramidDesc = m_DepthPyramidBufferDesc;
-                var pyramidSideSize = depthPyramidDesc.height;
+                var pyramidSideSize = depthPyramidDesc.width;
 
                 // The gaussian pyramid compute works in blocks of 8x8 so make sure the last lod has a
                 // minimum size of 8x8
 
             var pyramidSize = CalculatePyramidSize((int)hdCamera.screenSize.x, (int)hdCamera.screenSize.y);
 
-            // for stereo double-wide, each half of the texture will represent a single eye's pyramid 
+            // for stereo double-wide, each half of the texture will represent a single eye's pyramid
             //var widthModifier = 1;
             //if (stereoEnabled && (desc.dimension != TextureDimension.Tex2DArray))
             //    widthModifier = 2; // double-wide

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScattering.hlsl

 // SSSBuffer texture declaration
 TEXTURE2D(_SSSBufferTexture0);
 
+// Note: The SSS buffer used here is sRGB
+// Note: The SSS buffer used here is sRGB
 void DecodeFromSSSBuffer(float4 sssBuffer, uint2 positionSS, out SSSData sssData)
 {
     sssData.diffuseColor = sssBuffer.rgb;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScatteringManager.cs

         // for SSS
         public void InitSSSBuffersFromGBuffer(GBufferManager gbufferManager)
         {
-            m_RTIDs[0] = gbufferManager.GetGBuffers()[0];
+            m_RTIDs[0] = gbufferManager.GetGBuffers()[0]; // Note: This buffer must be sRGB (which is the case with Lit.shader)
         }
 
         // In case of full forward we must allocate the render target for forward SSS (or reuse one already existing)
 
             desc.depthBufferBits = 0;
             desc.colorFormat = RenderTextureFormat.ARGB32;
-            desc.sRGB = false;
+            desc.sRGB = true;  // Note: This buffer must be sRGB to match deferred case (which is the case with Lit.shader)
 
             cmd.ReleaseTemporaryRT(m_SSSBuffer0);
             cmd.GetTemporaryRT(m_SSSBuffer0, desc, FilterMode.Point);