[llvm] [RISCV] Reduce the number of parameters to copyPhysRegVector. NFC (PR #70502)

[Philip Reames via llvm-commits]

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

LGTM

I might be tempted to invert the lookup and pass the LMUL instead of the copy opcode for the LMUL.  

https://github.com/llvm/llvm-project/pull/70502