batman-adv: Delete unnecessary checks before the function call "kfree_skb"

The kfree_skb() function tests whether its argument is NULL and then
returns immediately. Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

net/batman-adv/main.c

@@ -1184,7 +1184,7 @@ void batadv_tvlv_unicast_send(struct batadv_priv *bat_priv, u8 *src,
 		ret = true;
 
 out:
-	if (skb && !ret)
+	if (!ret)
 		kfree_skb(skb);
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);

net/batman-adv/network-coding.c

@@ -244,9 +244,7 @@ static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
  */
 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet)
 {
-	if (nc_packet->skb)
-		kfree_skb(nc_packet->skb);
-
+	kfree_skb(nc_packet->skb);
 	batadv_nc_path_free_ref(nc_packet->nc_path);
 	kfree(nc_packet);
 }

net/batman-adv/send.c

@@ -407,8 +407,7 @@ void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)
 
 static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
 {
-	if (forw_packet->skb)
-		kfree_skb(forw_packet->skb);
+	kfree_skb(forw_packet->skb);
 	if (forw_packet->if_incoming)
 		batadv_hardif_free_ref(forw_packet->if_incoming);
 	if (forw_packet->if_outgoing)