[IPV6]: Need to use pskb_trim_rcsum().

Fix pskb_trim usage in ipv6. Only the udp one is really
a bug, other places are just doing equivalent code.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 9d9e043..e4fe9ee 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -479,12 +479,9 @@
 	/* Point into the IP datagram 'data' part. */
 	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 		goto err;
-	if (end-offset < skb->len) {
-		if (pskb_trim(skb, end - offset))
-			goto err;
-		if (skb->ip_summed != CHECKSUM_UNNECESSARY)
-			skb->ip_summed = CHECKSUM_NONE;
-	}
+	
+	if (pskb_trim_rcsum(skb, end - offset))
+		goto err;
 
 	/* Find out which fragments are in front and at the back of us
 	 * in the chain of fragments so far.  We must know where to put