Since fd7edfcdc3 ("bridge: fix lookup for untagged packets in
bridge_transmit()") and b0e38a1373 ("bridge: distinguish no vlan and
vlan 1") we do a better job of distinguishing between untagged and VLAN
1 traffic.
However, ifconfig still defaulted to adding addresses for VLAN 1, rather
than for untagged traffic. Change this to be the most common (i.e.
untagged) option.