[llvm] [RISCV] Use VECREDUCE_OR instead of VP_REDUCE_OR in combineVectorSizedSetCCEquality. NFCish (PR #207122)

[Pengcheng Wang via llvm-commits]

wangpc-pp wrote:

I think It should be totally NFC now. I used VP node at that time because it caused extra `vsetvli` (https://github.com/llvm/llvm-project/pull/114971#discussion_r1831095689) but it should be fixed now.

https://github.com/llvm/llvm-project/pull/207122