tcp: Do not reload skb pointer after skb_gro_receive().

This is not necessary. skb_gro_receive() will never change what
'head' points to.

In it's original implementation (see commit 71d93b39e52e ("net: Add
skb_gro_receive")), it did:

====================
+ *head = nskb;
+ nskb->next = p->next;
+ p->next = NULL;
====================

This sequence was removed in commit 58025e46ea2d ("net: gro: remove
obsolete code from skb_gro_receive()")

Signed-off-by: David S. Miller <[e-mail]>
Signed-off-by: Eric Dumazet <[e-mail]>

net/ipv4/tcp_offload.c

···
 		goto out_check_final;
 	}
 
-	p = *head;
-	th2 = tcp_hdr(p);
 	tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
 
 out_check_final: