mac80211: verify virtual interfaces in driver API

The driver is never informed about monitor or
AP_VLAN interfaces, so whenever we pass those
to it later this is a bug. Verify we don't as
there are some cases where this could happen.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>