staging: vt6655: check ieee80211_bss_conf bssid not NULL

commit 8e8e9198 upstream.

Sometimes bssid can go null on failed association.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/device_main.c

@@ -1417,7 +1417,7 @@ static void vnt_bss_info_changed(struct ieee80211_hw *hw,
 
 	priv->current_aid = conf->aid;
 
-	if (changed & BSS_CHANGED_BSSID) {
+	if (changed & BSS_CHANGED_BSSID && conf->bssid) {
 		unsigned long flags;
 
 		spin_lock_irqsave(&priv->lock, flags);