net: gro: avoid double copy in skb_gro_receive()

__copy_skb_header(nskb, p) already copied p->cb[], no need to copy
it again.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/skbuff.c

@@ -3028,7 +3028,6 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
 	memcpy(skb_mac_header(nskb), skb_mac_header(p),
 	       p->data - skb_mac_header(p));
 
-	*NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
 	skb_shinfo(nskb)->frag_list = p;
 	skb_shinfo(nskb)->gso_size = pinfo->gso_size;
 	pinfo->gso_size = 0;