ip_gre: allow CSUM capable devices to handle packets

If device is not able to handle checksumming it will
be handled in dev_xmit

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_gre.c

@@ -745,11 +745,8 @@ static struct sk_buff *handle_offloads(struct sk_buff *skb)
 			goto error;
 		skb_shinfo(skb)->gso_type |= SKB_GSO_GRE;
 		return skb;
-	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		err = skb_checksum_help(skb);
-		if (unlikely(err))
-			goto error;
 	}
+	if (skb->ip_summed != CHECKSUM_PARTIAL)
 		skb->ip_summed = CHECKSUM_NONE;
 
 	return skb;