[clang] [llvm] [RISCV] Add processor definitions for XuanTie C910V2 and C920V2 (PR #174056)

[Wang Yaduo via cfe-commits]

MouseSplinter wrote:

> > ping
> 
> There is already an approval, you can just merge it after resolving the conflict.

There is no merge button in my side, it seems that I no longer have the commit access with the new policy, could you help me to merge this. :)

https://github.com/llvm/llvm-project/pull/174056