[llvm] [AArch64] Add patterns for conversions using fixed-point scvtf (PR #92922)

[David Green via llvm-commits]

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

Thanks - This looks great, and I couldn't figure out any way in which it wouldn't match the version with a fmul/fdiv like the pseudo code. LGTM

https://github.com/llvm/llvm-project/pull/92922