[llvm-branch-commits] [llvm] AMDGPU: Add some release 20 notes (PR #128136)

[via llvm-branch-commits]

github-actions[bot] wrote:

@arsenm (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix.  When you are done, please add the release:note label to this PR. 

https://github.com/llvm/llvm-project/pull/128136