batman-adv: Place kref_get for dat_entry 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/distributed-arp-table.c

@@ -343,8 +343,8 @@ static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
 	ether_addr_copy(dat_entry->mac_addr, mac_addr);
 	dat_entry->last_update = jiffies;
 	kref_init(&dat_entry->refcount);
-	kref_get(&dat_entry->refcount);
 
+	kref_get(&dat_entry->refcount);
 	hash_added = batadv_hash_add(bat_priv->dat.hash, batadv_compare_dat,
 				     batadv_hash_dat, dat_entry,
 				     &dat_entry->hash_entry);