[clang] [X86] Finally handle target of __builtin_ia32_cmp[p|s][s|d] from avx into sse/sse2/avx (PR #84136)

[Freddy Ye via cfe-commits]

FreddyLeaf wrote:

> Thanks for the heads-up @RKSimon I've made suggestions for consistency with existing practice in emmintrin.h which I've adopted in the latest revision to #83316.
> 
> I'm unsure how replacing a function declaration with an \fn directive will play with our documentation tooling. But we can figure that out later.

I've committed your suggestions. FYI \fn usage was referring https://github.com/llvm/llvm-project/blob/c58c8278f98c189d149d5f062b8d4f56efcada90/clang/lib/Headers/avxvnniintrin.h#L32


https://github.com/llvm/llvm-project/pull/84136