[llvm] [RISCVGatherScatterLowering] Support vp_gather and vp_scatter (PR #73612)

[Craig Topper via llvm-commits]

topperc wrote:

I'm not opposed to this patch, but I thought the BSC vectorizer that produces VP intrinics emits strided load/stores directly?

@rofirrim 

https://github.com/llvm/llvm-project/pull/73612