cfg80211: don't parse MBSSID if transmitting BSS isn't created

Don't parse the multi-BSSID structures if we couldn't even create
their transmitting BSS, this would confuse all of our tracking.

This also means that non_tx_data->tx_bss will never be NULL, so
we can clean up a little bit.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Link: https://lore.kernel.org/r/20190703133823.10530-2-johannes@sipsolutions.netSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/scan.c

@@ -1440,7 +1440,7 @@ cfg80211_inform_single_bss_data(struct wiphy *wiphy,
 			regulatory_hint_found_beacon(wiphy, channel, gfp);
 	}
 
-	if (non_tx_data && non_tx_data->tx_bss) {
+	if (non_tx_data) {
 		/* this is a nontransmitting bss, we need to add it to
 		 * transmitting bss' list if it is not there
 		 */
@@ -1659,6 +1659,8 @@ cfg80211_inform_bss_data(struct wiphy *wiphy,
 	res = cfg80211_inform_single_bss_data(wiphy, data, ftype, bssid, tsf,
 					      capability, beacon_interval, ie,
 					      ielen, NULL, gfp);
+	if (!res)
+		return NULL;
 	non_tx_data.tx_bss = res;
 	cfg80211_parse_mbssid_data(wiphy, data, ftype, bssid, tsf,
 				   beacon_interval, ie, ielen, &non_tx_data,