[llvm] [SelectionDAG][RISCV] Move VP_REDUCE* legalization to LegalizeDAG.cpp. (PR #90522)

[Craig Topper via llvm-commits]

topperc wrote:

I notice we might be missing support for non-VP reductions for f16 with vectors with Zfhmin.

https://github.com/llvm/llvm-project/pull/90522