[clang] [llvm] [RFC][RISCV] Support RISC-V Profiles in -march option (PR #76357)

[Wang Pengcheng via cfe-commits]

W-angler wrote:

Current implementation is based on the comment(https://github.com/riscv-non-isa/riscv-toolchain-conventions/pull/36#issuecomment-1867859642), not the RFC. @dtcxzyw 

https://github.com/llvm/llvm-project/pull/76357