batman-adv: Fix double-put of vlan object

Each batadv_tt_local_entry hold a single reference to a
batadv_softif_vlan.  In case a new entry cannot be added to the hash
table, the error path puts the reference, but the reference will also
now be dropped by batadv_tt_local_entry_release().

Fixes: a33d970d ("batman-adv: Fix reference counting of vlan object for tt_local_entry")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/batman-adv/translation-table.c

@@ -693,7 +693,6 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const u8 *addr,
 	if (unlikely(hash_added != 0)) {
 		/* remove the reference for the hash */
 		batadv_tt_local_entry_put(tt_local);
-		batadv_softif_vlan_put(vlan);
 		goto out;
 	}