cfg80211: fix disassociation warning due to misuse of wdev->current_bss

WARN_ON was triggered at mlme.c:213 when dissociating from an AP.

wdev->current_bss->pub.bssid should be used in place of
wdev->current_bss for BSSID comparison.
Signed-off-by: NPavel Roskin <proski@gnu.org>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/wireless/mlme.c

@@ -198,7 +198,7 @@ static void __cfg80211_send_disassoc(struct net_device *dev,
 		return;
 
 	if (wdev->current_bss &&
-	    memcmp(wdev->current_bss, bssid, ETH_ALEN) == 0) {
+	    memcmp(wdev->current_bss->pub.bssid, bssid, ETH_ALEN) == 0) {
 		for (i = 0; i < MAX_AUTH_BSSES; i++) {
 			if (wdev->authtry_bsses[i] || wdev->auth_bsses[i])
 				continue;