[compiler-rt] [RISCV] Support rv{32, 64}e in the compiler builtins (PR #88252)

[via llvm-commits]

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

@xermicus Thanks for the PR! I was meaning to do this myself but it ended up being on the backburner. (:

LGTM

https://github.com/llvm/llvm-project/pull/88252