Cleanup: silence unused variable warning

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D8328

source/blender/draw/intern/draw_cache_impl_pointcloud.c

@@ -270,6 +270,7 @@ GPUBatch **DRW_cache_pointcloud_surface_shaded_get(Object *ob,
   PointCloud *pointcloud = ob->data;
   PointCloudBatchCache *cache = pointcloud_batch_cache_get(pointcloud);
   BLI_assert(cache->mat_len == gpumat_array_len);
+  UNUSED_VARS(gpumat_array_len);
 
   if (cache->surface_per_mat[0] == NULL) {
     pointcloud_batch_cache_ensure_pos(ob, cache);