The 4-address frames WDS design in mac80211 uses VLAN interfaces
similarly to the way VLAN interfaces based on VLAN IDs are used. The EAP
authentication case ended up overriding the WDS specific assignment even
when the RADIUS server did not assign any specific VLAN for the STA.
This broke WDS traffic.
Fix this by skipping VLAN assignment to VLAN ID 0 for STAs that have
been detected to use 4-address frames.
Signed-off-by: Jouni Malinen <j@w1.fi>