Bluetooth: 6lowpan: fix skb_unshare behaviour

This patch reverts commit:

a7807d73 ("Bluetooth: 6lowpan: Avoid memory leak if memory allocation
fails")

which was wrong suggested by Alexander Aring. The function skb_unshare
run also kfree_skb on failure.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org # 3.18.x

net/bluetooth/6lowpan.c

@@ -614,17 +614,13 @@ static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
 	int err = 0;
 	bdaddr_t addr;
 	u8 addr_type;
-	struct sk_buff *tmpskb;
 
 	/* We must take a copy of the skb before we modify/replace the ipv6
 	 * header as the header could be used elsewhere
 	 */
-	tmpskb = skb_unshare(skb, GFP_ATOMIC);
-	if (!tmpskb) {
-		kfree_skb(skb);
+	skb = skb_unshare(skb, GFP_ATOMIC);
+	if (!skb)
 		return NET_XMIT_DROP;
-	}
-	skb = tmpskb;
 
 	/* Return values from setup_header()
 	 *  <0 - error, packet is dropped