[llvm] [AArch64] Fix SVE cost model for various math intrinsics (PR #184358)

[David Green via llvm-commits]

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

Thanks - the other thing I thought of but forgot to mention was BF16. It looks like this isn't changing the scores, even if they are not great though, so LGTM.

https://github.com/llvm/llvm-project/pull/184358