mac802154: fakelb: Fix potential NULL pointer dereference.

fakelb_hw_deliver creates a copy of the skb's header which can
potentially return NULL so we now check for this before actually
delivering to the 802.15.4 MAC layer.
Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/fakelb.c

@@ -69,6 +69,7 @@ fakelb_hw_deliver(struct fakelb_dev_priv *priv, struct sk_buff *skb)
 	spin_lock(&priv->lock);
 	if (priv->working) {
 		newskb = pskb_copy(skb, GFP_ATOMIC);
+		if (newskb)
 			ieee802154_rx_irqsafe(priv->hw, newskb, 0xcc);
 	}
 	spin_unlock(&priv->lock);