Cycles: Metal graphics interop

This is trivial with unified memory, and avoids one memory copy.

Pull Request: https://projects.blender.org/blender/blender/pulls/137363

intern/cycles/device/cuda/device_impl.cpp

@@ -1122,6 +1122,7 @@ bool CUDADevice::should_use_graphics_interop(const GraphicsInteropDevice &intero
 
       return found;
     }
+    case GraphicsInteropDevice::METAL:
     case GraphicsInteropDevice::NONE: {
       return false;
     }