mac80211: fix crash when using AP VLAN interfaces

Commit "mac80211: implement SMPS for AP" applies to AP_VLAN as well.
It assumes that sta->sdata->vif.bss_conf.bssid is present, which did not
get set for AP_VLAN.
Initialize it to sdata->vif.addr like for other interface types.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/iface.c

@@ -1325,7 +1325,6 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
 		sdata->vif.bss_conf.bssid = NULL;
 		break;
 	case NL80211_IFTYPE_AP_VLAN:
-		break;
 	case NL80211_IFTYPE_P2P_DEVICE:
 		sdata->vif.bss_conf.bssid = sdata->vif.addr;
 		break;