[llvm] [AMDGPU][True16][MC] Support VOP3 only instructions with true16 and fake16 (PR #109891)

[Ivan Kosarev via llvm-commits]

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

LGTM, provided the test changes are not far from what we have downstream, so not much of manual work will be needed to merge them there. (Otherwise, please will you make sure to cherry-pick this downstream before submitting here. Thanks.)

https://github.com/llvm/llvm-project/pull/109891