netfilter: ipt_REJECT: avoid touching dst ref

We can avoid a pair of atomic ops in ipt_REJECT send_reset()

Signed-off-by: Eric Dumazet <[e-mail]>
Signed-off-by: Patrick McHardy <[e-mail]>

net/ipv4/netfilter/ipt_REJECT.c

···
 		addr_type = RTN_LOCAL;
 
 	/* ip_route_me_harder expects skb->dst to be set */
-	skb_dst_set(nskb, dst_clone(skb_dst(oldskb)));
+	skb_dst_set_noref(nskb, skb_dst(oldskb));
 
 	if (ip_route_me_harder(nskb, addr_type))
 		goto free_nskb;