cfg80211: clear connect keys when freeing them

When freeing the connect keys, clear the memory to avoid
having the key material stick around in memory "forever".

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/wext-sme.c

diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index c7e5c8e..368611c 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -57,7 +57,7 @@
 	err = cfg80211_connect(rdev, wdev->netdev,
 			       &wdev->wext.connect, ck, prev_bssid);
 	if (err)
-		kfree(ck);
+		kzfree(ck);
 
 	return err;
 }