[llvm] [RISCV] Add support for new unprivileged extensions defined in profiles spec (PR #77458)

[Alex Bradbury via llvm-commits]

asb wrote:

As RVA22 is ratified, I think treating this as non-experimental and v1.0 (as you have) makes sense. I'm wondering if Ziccrse, Ziccamoa, Za64rs, and Za128rs should imply A though?

https://github.com/llvm/llvm-project/pull/77458