[Driver] Mark m_x86_Features_Group options as TargetSpecific

so that they lead to an error when compiled for non-x86 targets.
Follow-up to D151590.

```
% aarch64-linux-gnu-gcc -c -mavx a.c
aarch64-linux-gnu-gcc: error: unrecognized command-line option ‘-mavx’
% clang --target=aarch64-unknown-linux-gnu -c -mavx a.c  # without this patch
clang: warning: argument unused during compilation: '-mavx' [-Wunused-command-line-argument]
...

% clang --target=aarch64-unknown-linux-gnu -c -mavx a.c  # with this patch
clang: error: unsupported option '-mavx' for target 'aarch64-unknown-linux-gnu'
```

As a workaround for https://github.com/llvm/llvm-project/issues/63270, we don't
report an error for -msse4.2.

Reviewed By: pengfei, skan

Differential Revision: https://reviews.llvm.org/D156962