station: Lookup preauth target on the network

There may be situations (due to Multi-BSS operation) where an AP might
be advertising multiple SSIDs on the same BSSID.  It is thus more
correct to lookup the preauthentication target on the network object
instead of the station bss_list.  It used to be that the network list of
bsses was not updated when roam scan was performed.  Hence the lookup
was always performed on the station bss_list.  But this is no longer the
case, so it is safer to lookup on the network object directly on the
network.

src/station.c

@@ -2136,8 +2136,8 @@ static void station_preauthenticate_cb(struct netdev *netdev,
 	if (!station->preparing_roam || result == NETDEV_RESULT_ABORTED)
 		return;
 
-	bss = l_queue_find(station->bss_list, bss_match_bssid,
-				station->preauth_bssid);
+	bss = network_bss_find_by_addr(station->connected_network,
+						station->preauth_bssid);
 	if (!bss) {
 		l_error("Roam target BSS not found");
 		station_roam_failed(station);