wifi: mac80211: do not pass AP_VLAN vif pointer to drivers during flush

This fixes WARN_ONs when using AP_VLANs after station removal. The flush
call passed AP_VLAN vif to driver, but because these vifs are virtual and
not registered with drivers, we need to translate to the correct AP vif
first.

Closes: https://github.com/openwrt/openwrt/issues/12420
Fixes: 0b75a1b ("wifi: mac80211: flush queues on STA removal")
Fixes: d00800a ("wifi: mac80211: add flush_sta method")
Tested-by: Konstantin Demin <rockdrilla@gmail.com>
Tested-by: Koen Vandeputte <koen.vandeputte@citymesh.com>
Signed-off-by: Oldřich Jedlička <oldium.pro@gmail.com>
Link: https://lore.kernel.org/r/20231104141333.3710-1-oldium.pro@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/driver-ops.h

@@ -23,7 +23,7 @@
 static inline struct ieee80211_sub_if_data *
 get_bss_sdata(struct ieee80211_sub_if_data *sdata)
 {
-	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+	if (sdata && sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 		sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
 				     u.ap);
 
@@ -695,11 +695,14 @@ static inline void drv_flush(struct ieee80211_local *local,
 			     struct ieee80211_sub_if_data *sdata,
 			     u32 queues, bool drop)
 {
-	struct ieee80211_vif *vif = sdata ? &sdata->vif : NULL;
+	struct ieee80211_vif *vif;
 
 	might_sleep();
 	lockdep_assert_wiphy(local->hw.wiphy);
 
+	sdata = get_bss_sdata(sdata);
+	vif = sdata ? &sdata->vif : NULL;
+
 	if (sdata && !check_sdata_in_driver(sdata))
 		return;
 
@@ -716,6 +719,8 @@ static inline void drv_flush_sta(struct ieee80211_local *local,
 	might_sleep();
 	lockdep_assert_wiphy(local->hw.wiphy);
 
+	sdata = get_bss_sdata(sdata);
+
 	if (sdata && !check_sdata_in_driver(sdata))
 		return;