[SK_BUFF]: Use skb_reset_network_header where the return of __pskb_pull was being used

It returns skb->data, so we can just use skb_reset_network_header after it.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ip_gre.c

@@ -617,7 +617,8 @@ static int ipgre_rcv(struct sk_buff *skb)
 		}
 
 		skb_reset_mac_header(skb);
-		skb->nh.raw = __pskb_pull(skb, offset);
+		__pskb_pull(skb, offset);
+		skb_reset_network_header(skb);
 		skb_postpull_rcsum(skb, skb->h.raw, offset);
 		skb->pkt_type = PACKET_HOST;
 #ifdef CONFIG_NET_IPGRE_BROADCAST