[llvm] [RISCV] Support llvm.masked.expandload intrinsic (PR #101954)

[Philip Reames via llvm-commits]

preames wrote:

LGTM - but please wait a bit in case Luke or Craig have remaining comments.  I think everything has been addressed, but maybe I missed something.

Please remember to update the review description before merging as that becomes the submission comment.  

https://github.com/llvm/llvm-project/pull/101954