[clang] [llvm] [AMDGPU] Add intrinsics and builtins for v_cvt_scale_pk32_* instructions (PR #222617)

[Krzysztof Drewniak via llvm-commits]

https://github.com/krzysz00 approved this pull request.

Looks fine to me, let's land these (mod minor doc wording quibbles)

https://github.com/llvm/llvm-project/pull/222617