[llvm] [RISCV] Add Vendor Reloc and Fallback Names (PR #116974)

[Jessica Clarke via llvm-commits]

jrtc27 wrote:

Yeah I've convinced myself that I have no issue with you moving ahead with this upstream. If this becomes a problem we can revisit the conversation at that later date.

https://github.com/llvm/llvm-project/pull/116974