coverity: exclude deprecated arm driver files

drivers/arm/mhu/mhu_v2_x.c
drivers/arm/mhu/mhu_wrapper_v2_x.c
drivers/arm/tzc/tzc_dmc620.c

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: If74d7996378b776503897f93efc84e2a482967da
1 file changed