[llvm] [RISCV] Add LD_RV32/SD_RV32 to a few more functions in RISCVInstrInfo. (PR #140640)

[Philip Reames via llvm-commits]

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

LGTM

Mildly not a fan of adding code which isn't yet exercised, but a) the change is obvious, and b) I trust you to follow through on the spill/fill bits in a reasonable timeline.  

https://github.com/llvm/llvm-project/pull/140640