[clang] [llvm] [clang-tools-extra] [AMDGPU][GFX12] Add Atomic cond_sub_u32 (PR #76224)

[Mariusz Sikora via cfe-commits]

mariusz-sikora-at-amd wrote:

Adding support in atomicrmw. This will require to add new operation to aromicrmw "cond_sub" or you had something else in mind @arsenm ?

https://github.com/llvm/llvm-project/pull/76224