[clang] [Clang][RISCV] Add preprocessor macros for Zicfilp CFI scheme (PR #109600)

[Kito Cheng via cfe-commits]

https://github.com/kito-cheng commented:

BTW, the LLVM using one PR one commit policy, it only allow `squash and merge`, so I would suggest you split this into 3 PR.

https://github.com/llvm/llvm-project/pull/109600