[llvm] AMDGPU: Add description for new atomicrmw metadata (PR #85052)

[via llvm-commits]

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@@ -73,6 +73,8 @@ Changes to the AMDGPU Backend
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 * Implemented the ``llvm.get.fpenv`` and ``llvm.set.fpenv`` intrinsics.
+* Added ``!amdgpu.no.access.location.types`` metadata to control
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b-sumner wrote:

Do we want to mention the other two new metadata here?

https://github.com/llvm/llvm-project/pull/85052