cleanup some commented out and unused code

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

 
                 // Depth texture is now ready, bind it.
                 cmd.SetGlobalTexture(HDShaderIDs._MainDepthTexture, GetDepthTexture());
-
-				// for alpha compositing, color is cleared to 0, alpha to 1
-				// https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch23.html
-
-//				Color clearColor = new Color(0.0f, 0.0f, 0.0f, 1.0f);
-//				HDUtils.SetRenderTarget(cmd, camera, m_DbufferManager.GetBuffersRTI(), m_CameraDepthStencilBuffer, ClearFlag.Color, clearColor);
-
-
-				// we need to do a separate clear for normals, because they are cleared to a different color
-//				Color clearColorNormal = new Color(0.5f, 0.5f, 0.5f, 1.0f); // for normals 0.5 is neutral
-//				m_DbufferManager.ClearNormalTargetAndHTile(cmd, camera, clearColorNormal);
-
 				HDUtils.SetRenderTarget(cmd, camera, m_DbufferManager.GetBuffersRTI(), m_CameraDepthStencilBuffer); // do not clear anymore
                 m_DbufferManager.SetHTile(m_DbufferManager.bufferCount, cmd);
                 DecalSystem.instance.RenderIntoDBuffer(cmd);

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/DBufferManager.cs

             HDUtils.SetRenderTarget(cmd, camera, m_HTile, ClearFlag.Color, CoreUtils.clearColorAllBlack);
         }
 
-        public void ClearNormalTargetAndHTile(CommandBuffer cmd, HDCamera camera, Color clearColor)
-        {
-            // index 1 is normals
-            HDUtils.SetRenderTarget(cmd, camera, m_RTs[1], ClearFlag.Color, clearColor);
-            HDUtils.SetRenderTarget(cmd, camera, m_HTile, ClearFlag.Color, CoreUtils.clearColorAllBlack);
-        }
-
         public void SetHTile(int bindSlot, CommandBuffer cmd)
         {
             cmd.SetRandomWriteTarget(bindSlot, m_HTile);