batman-adv: Place kref_get for tt_common near use

It is hard to understand why the refcnt is increased when it isn't done
near the actual place the new reference is used. So using kref_get right
before the place which requires the reference and in the same function
helps to avoid accidental problems caused by incorrect reference counting.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/translation-table.c

@@ -1645,13 +1645,13 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
 		if (flags & BATADV_TT_CLIENT_ROAM)
 			tt_global_entry->roam_at = jiffies;
 		kref_init(&common->refcount);
-		kref_get(&common->refcount);
 		common->added_at = jiffies;
 
 		INIT_HLIST_HEAD(&tt_global_entry->orig_list);
 		atomic_set(&tt_global_entry->orig_list_count, 0);
 		spin_lock_init(&tt_global_entry->list_lock);
 
+		kref_get(&common->refcount);
 		hash_added = batadv_hash_add(bat_priv->tt.global_hash,
 					     batadv_compare_tt,
 					     batadv_choose_tt, common,