[llvm] AMDGPU: Start fixing inconsistencies in usage of SubtargetPredicate (PR #96337)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> This is almost impossible to judge the consequences. I guess you need these applied to all downstream branches first and see it anything is broken.

This was so I could merge my assorted atomic patches into the downstream branches. It's too difficult to wrangle the isGFXY style checks 


https://github.com/llvm/llvm-project/pull/96337