Fix shadowmask warning + lightmap warning

- Fix warning about shadowmask index not being bing
- Fix warning about decode instruction in lightmap already bind

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipelineAsset.asset

     supportSSAO: 1
     supportSubsurfaceScattering: 1
     supportForwardOnly: 0
+    enableUltraQualitySSS: 0
     supportDBuffer: 1
     supportMSAA: 0
     msaaSampleCount: 1

ScriptableRenderPipeline/HDRenderPipeline/HDRP/MRTBufferManager.cs

 
         public abstract void CreateBuffers();
 
-        public void BindBufferAsTextures(CommandBuffer cmd)
+        public virtual void BindBufferAsTextures(CommandBuffer cmd)
         {
             for (int i = 0; i < m_BufferCount; ++i)
             {

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/GBufferManager.cs

 using UnityEngine.Rendering;
+using UnityEngine.Rendering.PostProcessing;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
-        bool m_EnableShadowMask = false;
+        bool m_SupportShadowMask = false;
         RenderPipelineMaterial m_DeferredMaterial;
         protected RenderTargetIdentifier[] m_RTIDsNoShadowMask;
 
 
             m_DeferredMaterial = deferredMaterial;
             m_GBufferCount = deferredMaterial.GetMaterialGBufferCount();
-            m_EnableShadowMask = enableBakeShadowMask;
+            m_SupportShadowMask = enableBakeShadowMask;
 
             m_RTIDsNoShadowMask = new RenderTargetIdentifier[m_GBufferCount];
         }
                 m_RTIDsNoShadowMask[gbufferIndex] = HDShaderIDs._GBufferTexture[gbufferIndex];
             }
 
-            if (m_EnableShadowMask)
+            if (m_SupportShadowMask)
+            }
+        }
+
+        public override void BindBufferAsTextures(CommandBuffer cmd)
+        {
+            for (int i = 0; i < m_BufferCount; ++i)
+            {
+                cmd.SetGlobalTexture(m_TextureShaderIDs[i], m_RTs[i]);
+            }
+
+            // When shadow mask are disabled (i.e we haven't created shadow mask texture, bind a white texture).
+            if (!m_SupportShadowMask)
+            {
+                cmd.SetGlobalTexture(HDShaderIDs._ShadowMaskTexture, RuntimeUtilities.whiteTexture);
             }
         }
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/MaterialUtilities.hlsl

     #if defined(UNITY_LIGHTMAP_RGBM_ENCODING)
         float4 decodeInstructions = float4(34.493242, 2.2, 0.0, 0.0); // range^2.2 = 5^2.2, gamma = 2.2
     #else
-        float4 decodeInstructions = float4(0.0, 0.0, 0.0, 0.0); // range = 2.0^2.2 = 4.59
+        float4 decodeInstructions = float4(2.0, 2.2, 0.0, 0.0); // range = 2.0^2.2 = 4.59
     #endif
 #endif
 
     #endif
 
     #ifdef DYNAMICLIGHTMAP_ON
-        float4 decodeInstructions = float4(0.0, 0.0, 0.0, 0.0); // Never used but needed for the interface since it supports gamma lightmaps
         #ifdef DIRLIGHTMAP_COMBINED
         bakeDiffuseLighting += SampleDirectionalLightmap(TEXTURE2D_PARAM(unity_DynamicLightmap, samplerunity_DynamicLightmap),
                                                         TEXTURE2D_PARAM(unity_DynamicDirectionality, samplerunity_DynamicLightmap),