[llvm] [X86] Add constant comments for VGF2P8AFFINEQB rmbi forms (PR #194789)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon requested changes to this pull request.

Please can you regenerate all llvm\test\CodeGen\X86\*gfni*.ll files?  Otherwise we get regeneration churn the next time they are touched.

https://github.com/llvm/llvm-project/pull/194789