[llvm] [RISCV][ISel] Add ISel support for experimental Zimop extension (PR #77089)

[Craig Topper via llvm-commits]

topperc wrote:

> This implements ISel support for mopr[0-31] and moprr[0-8] instructions for 32 and 64 bits

Should that be moprr[0-7]?

https://github.com/llvm/llvm-project/pull/77089