ipv6: remove assignment in if condition

Do assignment before if condition and test !skb like in rawv6_recvmsg()

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 896af88..075a0fb 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -548,7 +548,8 @@
 	if (!rp->checksum)
 		goto send;
 
-	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
+	skb = skb_peek(&sk->sk_write_queue);
+	if (!skb)
 		goto out;
 
 	offset = rp->offset;