Simplify hardswish ONNX export graph. (#60080)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/58301
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60080
Reviewed By: suo
Differential Revision: D30002939
Pulled By: SplitInfinity
fbshipit-source-id: 8b4ca6f62d51b72e9d86534592e3c82ed6608c9d
