openvswitch: Compute checksum in skb_gso_segment() if needed

The copy & csum optimization is no longer present with zerocopy
enabled. Compute the checksum in skb_gso_segment() directly by
dropping the HW CSUM capability from the features passed in.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Jesse Gross <jesse@nicira.com>

net/openvswitch/datapath.c

@@ -311,7 +311,7 @@ static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb,
 	struct sk_buff *segs, *nskb;
 	int err;
 
-	segs = __skb_gso_segment(skb, NETIF_F_SG | NETIF_F_HW_CSUM, false);
+	segs = __skb_gso_segment(skb, NETIF_F_SG, false);
 	if (IS_ERR(segs))
 		return PTR_ERR(segs);