ndisc: Use skb_linearize() instead of pskb_may_pull(skb, skb->len).

Suggested by Eric Dumazet <edumazet@google.com>.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ndisc.c

@@ -1509,7 +1509,7 @@ int ndisc_rcv(struct sk_buff *skb)
 {
 	struct nd_msg *msg;
 
-	if (!pskb_may_pull(skb, skb->len))
+	if (skb_linearize(skb))
 		return 0;
 
 	msg = (struct nd_msg *)skb_transport_header(skb);