[clang] [llvm] AMDGPU: Builtin & CodeGen support for v_cvt_scalef32_sr_pk_fp4 instructions (PR #117798)

[Matt Arsenault via cfe-commits]

arsenm wrote:

### Merge activity

* **Nov 26, 7:57 PM EST**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/117798).


https://github.com/llvm/llvm-project/pull/117798