ipv6: result of csum_fold() is already 16bit, no need to cast

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6mr.c

@@ -358,7 +358,7 @@ static int pim6_rcv(struct sk_buff *skb)
 	if (pim->type != ((PIM_VERSION << 4) | PIM_REGISTER) ||
 	    (pim->flags & PIM_NULL_REGISTER) ||
 	    (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
-	     (u16)csum_fold(skb_checksum(skb, 0, skb->len, 0))))
+	     csum_fold(skb_checksum(skb, 0, skb->len, 0))))
 		goto drop;
 
 	/* check if the inner packet is destined to mcast group */