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

RISCVGatherScatterLowering is the last user of
riscv_masked_strided_{load,store} after #98131 and #98112, this patch
changes it to emit the VP equivalent instead. This allows us to remove
the masked_strided intrinsics so we have only have one lowering path.

riscv_masked_strided_{load,store} didn't have AVL operands and were
always VLMAX, so this passes in the fixed or scalable element count to
the EVL instead, which RISCVVectorPeephole should now convert to VLMAX
after #97800.
For loads we also use a vp_select to get passthru (mask undisturbed)
behaviour

0 files changed, 0 insertions, 0 deletions