Alignas is now correctly handled on ROCm (#16920)
Summary:
Post 2.1 release, packing is fixed and alignas works as expected.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16920
Differential Revision: D14018539
Pulled By: bddppq
fbshipit-source-id: 0ed4d9e9f36afb9b970812c3870082fd7f905455
