[llvm] [RISCV] Use templates to reduce duplicated code for assembler operand predicates. (PR #133351)

[Sam Elliott via llvm-commits]

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

This has been a bit overdue, thank you.

I have been having thoughts about how we deal with the Immedate or Symbol Expression variants, which I might attack as a follow-up.

https://github.com/llvm/llvm-project/pull/133351