[llvm] [RISCV] Reduce the interface to RISCVCCAssignFn. NFC (PR #107503)

[Craig Topper via llvm-commits]

topperc wrote:

> LGTM.
> 
> (There are about three PRs that need to rebase and merge one by one).

Yes. I wasn't sure which would be accepted so I didn't make the dependent. Should be pretty simple rebases.

https://github.com/llvm/llvm-project/pull/107503