[llvm] [RISCV] Lower vfmv.s.f intrinsics to VFMV_S_F_VL first (PR #76699)

[Philip Reames via llvm-commits]

https://github.com/preames requested changes to this pull request.

Needs rebased after https://github.com/llvm/llvm-project/pull/76801, marking as request changes to reflect and make it easier to scan review list for actionable items.  

https://github.com/llvm/llvm-project/pull/76699