Fix undersized cluster data buffer

Fix bug described here: https://forum.unity.com/threads/argumentexception-when-rendering-lots-of-runtime-lights-w-o-shadows.1462619/#post-9737638

Author: alelievr

Packages/com.unity.render-pipelines.high-definition/Runtime/Lighting/LightLoop/LightLoop.cs

@@ -728,7 +728,7 @@ void InitializeLightLoop(IBLFilterBSDF[] iBLFilterBSDFArray)
             // All the allocation of the compute buffers need to happened after the kernel finding in order to avoid the leak loop when a shader does not compile or is not available
             m_LightLoopLightData.Initialize(m_MaxDirectionalLightsOnScreen, m_MaxPunctualLightsOnScreen, m_MaxAreaLightsOnScreen, m_MaxEnvLightsOnScreen, m_MaxDecalsOnScreen);
 
-            m_TileAndClusterData.Initialize(allocateTileBuffers: true, clusterNeedsDepth: k_UseDepthBuffer, maxLightCount: m_MaxLightsOnScreen);
+            m_TileAndClusterData.Initialize(allocateTileBuffers: true, clusterNeedsDepth: k_UseDepthBuffer, maxLightCount: m_MaxLightsOnScreen + m_MaxDecalsOnScreen); // both light and decals are stored in the cluster
 
             // Setup shadow algorithms
             var shadowParams = asset.currentPlatformRenderPipelineSettings.hdShadowInitParams;
@@ -863,7 +863,7 @@ static int NumLightIndicesPerClusteredTile()
 
         void LightLoopAllocResolutionDependentBuffers(HDCamera hdCamera, int width, int height)
         {
-            m_TileAndClusterData.AllocateResolutionDependentBuffers(hdCamera, width, height, m_MaxViewCount, m_MaxLightsOnScreen);
+            m_TileAndClusterData.AllocateResolutionDependentBuffers(hdCamera, width, height, m_MaxViewCount, m_MaxLightsOnScreen + m_MaxDecalsOnScreen);
         }
 
         void LightLoopReleaseResolutionDependentBuffers()