[llvm] [TableGen] Use bitwise operations to access HwMode ID. (PR #88377)

[Jason Eckhardt via llvm-commits]

https://github.com/nvjle approved this pull request.

Thank you @superZWT123, all concerns have been addressed-- and this now passes when incorporated to our downstream back end.

LGTM, ready to land.

https://github.com/llvm/llvm-project/pull/88377