Note:
If you're using tagged VLANs according to IEEE 802.1Q and as soon as you set sysctl -w net.bridge.bridge-nf-call-iptables=1 you need two special rules, because OpenWRTs default FORWARD policy is to drop and none of the predefined policies will match. So your SSIDs configured to a VLAN won't work anymore.
When using a VLAN19 like described there Use SSID in specific VLAN - Wifi connection can not be established - #15 by VLANMaster you need these settings:
iptables -I FORWARD -m physdev --physdev-in eth0.19 -m comment --comment "VLAN19" -j ACCEPT
iptables -I FORWARD -m physdev --physdev-out eth0.19 -m comment --comment "VLAN19" -j ACCEPT