[llvm] [AArch64][ISel] Add support for v8.4a RCpc `ldapur`/`stlur` (PR #67879)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

Yeah it looks like it will be very rare, if it comes up at all.

LGTM, sorry for the delay in getting the review.

https://github.com/llvm/llvm-project/pull/67879