[llvm] AMDGPU: Make vector_shuffle legal for v2i32 with v_pk_mov_b32 (PR #123684)

[Matt Arsenault via llvm-commits]

arsenm wrote:

### Merge activity

* **Jan 23, 8:56 AM EST**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/123684).


https://github.com/llvm/llvm-project/pull/123684