[llvm] Revert "[AMDGPU] MCExpr-ify MC layer kernel descriptor" (PR #86151)

[via llvm-commits]

goldsteinn wrote:

If you have a fix ready thats fine too. Just FYI, you generally don't need to create a PR for a revert, you can just do it.

LGTM.

https://github.com/llvm/llvm-project/pull/86151