[clang] [CIR][AArch64] Lower remaining FP16 vfma and vfms builtins (PR #210359)

[Andrzej Warzyński via cfe-commits]

https://github.com/banach-space approved this pull request.

LGTM

This concludes "fused multiply-accumulate", well done @yairbenavraham ! Many thanks for seeing this through - it's been one of the trickiest groups to handle! Fantastic and much appreciated work 🙏🏻 

https://github.com/llvm/llvm-project/pull/210359