net: remove open-coded skb_cow_head.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2421,8 +2421,8 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
 
 		skb_warn_bad_offload(skb);
 
-		if (skb_header_cloned(skb) &&
-		    (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		err = skb_cow_head(skb, 0);
+		if (err < 0)
 			return ERR_PTR(err);
 	}