[clang] [CIR] Add NYI for fmaximum/fminimum/fmaximum_num/fminimum_num atomics (PR #206502)

[Sirui Mu via cfe-commits]

https://github.com/Lancern approved this pull request.

LGTM

I'm working on atomic libcall support recently and I'll take the implementation of these intrinsics.

https://github.com/llvm/llvm-project/pull/206502