[llvm] [AMDGPU] Skip non-wwm reg implicit-def from bb prolog (PR #115834)

[Christudasan Devadasan via llvm-commits]

cdevadas wrote:

### Merge activity

* **Nov 12, 1:00 PM EST**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/115834).


https://github.com/llvm/llvm-project/pull/115834