[clang] [clang] Allow MCTargetOptions to be parseable by -mllvm. (PR #66347)

[via cfe-commits]

hstk30-hw wrote:

Some project use `Werror`  strictly,
https://github.com/ClangBuiltLinux/linux/issues/306 add the `-no-deprecated-warn` option, 
but we can't pass the flags from clang to llvm-mc, change the makefile to use `llvm-mc` to generate obj just for some file is inconvenience.

https://github.com/llvm/llvm-project/pull/66347