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

[Jay Foad via llvm-commits]

jayfoad wrote:

I have only just noticed that there is a corresponding target feature called "hasRestrictedSOffset". Should I rename that too?

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