fix extensions build flags on newer GPUs (#47585)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/47352
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47585
Reviewed By: heitorschueroff
Differential Revision: D24833654
Pulled By: ezyang
fbshipit-source-id: eaec5b8db5f35cac0a74d2858cb054a3853b0990
