[llvm] [RISCV] Emit VP strided loads/stores in RISCVGatherScatterLowering (PR #98111)

[Luke Lau via llvm-commits]

lukel97 wrote:

I'll hold off until the LLVM 19 release branch is cut before landing this, I'm not worried about it but it's not particularly urgent either

https://github.com/llvm/llvm-project/pull/98111