Add a way to disable contribution of punctual lights

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/Volumetrics/Resources/VolumetricLighting.compute

     #define VBUFFER_SLICE_COUNT 256
 #endif
 
-#define SUPPORT_ASYMMETRY 1 // Support asymmetric phase functions
+#define SUPPORT_ASYMMETRY       1 // Support asymmetric phase functions
+#define SUPPORT_PUNCTUAL_LIGHTS 1 // Punctual lights contribute to fog lighting
 
 #define GROUP_SIZE_1D 16
 #define GROUP_SIZE_2D (GROUP_SIZE_1D * GROUP_SIZE_1D)
             lighting.radianceComplete += phase * intensity * color;
         }
     }
+
+#if (SUPPORT_PUNCTUAL_LIGHTS == 0)
+    return lighting;
+#endif
 
 #ifdef LIGHTLOOP_TILE_PASS
     // Loop over 1 or 2 light clusters.