Apply hip vs hipcc compilation flags correctly for building extensions (#46273)
Summary:
Fixes issues when building certain PyTorch extensions where the cpp files do NOT compile if flags such as `__HIP_NO_HALF_CONVERSIONS__` are defined.
cc jeffdaily
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46273
Reviewed By: zou3519
Differential Revision: D24422463
Pulled By: ezyang
fbshipit-source-id: 7a43d1f7d59c95589963532ef3bd3c68cb8262be
