[llvm] [AMDGPU] Rename hasGFX12Enc to hasInlineSOffset in BUF definitions. NFC. (PR #83434)

[Piotr Sobczak via llvm-commits]

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

LGTM, the name is certainly clearer than the gfxip number.

I am not sure if "inline" without "constant" in the name is intuitively understood by someone not familiar with the code (would "hasImmSOffset" be better?), but it is clear for me.

https://github.com/llvm/llvm-project/pull/83434