These CLI flags are clang specific. Move them- Only apply the previously added CWARNFLAGS to `CFLAGS.clang` sodrv.c` instead of they
don't get passed to gcc by accident, resulting in build failures with whole module.
that compiler- Only apply `-Wno-initializer-overrides` to CWARNFLAGS in the clang
scenario as it's not supported with gcc.
This fixes building the module with gcc and avoids accidentally
introducing tech debt with the module, in the event other issues are
accidentally introduced.
MFC after: 3 days
Fixes: 6b627f8858 ("iwlwifi: update Intel's mvm/mld drivers")