[clang] [llvm] [RISCV] Add generic CPUs for profiles (PR #84877)

[Pengcheng Wang via cfe-commits]

wangpc-pp wrote:

> Do you see any disadvantage to going back to adding a feature for the profiles?

Of course not, I will revise this patch tomorrow. Thanks for discussing this!
(I missed the sync-up meeting because I forgot the daylight saving...)

https://github.com/llvm/llvm-project/pull/84877