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

[Cyrill Leutwiler via llvm-commits]

xermicus wrote:

@wangpc-pp thanks for merging! Should this be backported to `release/18.x`?

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