ARC: MWDT: avoid xcheck object linkage as we don't use xcheck

We don't use xcheck (we disable it by passing '-Hnoxcheck' to
linker) so let's avoid xcheck object linkage as well by
passing '-Hnoxcheck_obj' option.

'-Hnoxcheck_obj' option implies the '-Hnoxcheck' option.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>