iwlwifi: mvm: clean interfaces on drv_stop

If a HW recovery was started but not completed since all interfaces went
down, make sure to cleanup all interfaces before clearing the HW_RESTART
flag.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>