ARC: MWDT: don't link MetaWare hostlink lib ever

MetaWare hostlink is a library of system calls for debugging.
We don't use in case of Zephyr, however we provide real system
calls implementations. Let's pass -Hhostlib= to MWDT linker to
eliminate the MetaWare hostlink library from linkage.

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