[caffe2/detectron2] fix Mask R-CNN caffe2 conversion on GPU (#36366)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36366
fix issues introduced in D20528758
Reviewed By: linbinyu
Differential Revision: D20959367
fbshipit-source-id: 920055a6782b9c6729177f7101f2f9eb3e40ebf8
