Fix: Cycles Metal issue rendering with multiple NanoVDB grids

After recent changes in b4be954856, pointer was written at the wrong offset.

intern/cycles/device/metal/queue.mm

@@ -376,7 +376,7 @@ void MetalDeviceQueue::init_execution()
       }
       else {
         /* The GPU address of a 1D buffer texture is written into the slot data field. */
-        write_resource(&texture_info[slot].data, id<MTLBuffer>(texture_slot_map[slot]), slot);
+        write_resource(&texture_info[slot].data, id<MTLBuffer>(texture_slot_map[slot]), 0);
       }
     }
   }