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>
diff --git a/net/wireless/util.c b/net/wireless/util.c
index a8b2816..5e233a5 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -797,7 +797,7 @@
 				netdev_err(dev, "failed to set mgtdef %d\n", i);
 	}
 
-	kfree(wdev->connect_keys);
+	kzfree(wdev->connect_keys);
 	wdev->connect_keys = NULL;
 }