[llvm] [AMDGPU] Do not generate V_FMAC_DX9_ZERO_F32 on GFX12 (PR #171116)

[Qinkun Bao via llvm-commits]

qinkunbao wrote:

Hi, can you take a look at https://lab.llvm.org/buildbot/#/builders/51/builds/28255?

I think the PR broke the sanitizer buildbot?

https://github.com/llvm/llvm-project/pull/171116