openvswitch: checking wrong variable in queue_userspace_packet()

"skb" is non-NULL here, for example we dereference it in skb_clone().
The intent was to test "nskb" which was just set.

Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Jesse Gross <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/openvswitch/datapath.c

···
 			return -ENOMEM;
 
 		nskb = __vlan_put_tag(nskb, vlan_tx_tag_get(nskb));
-		if (!skb)
+		if (!nskb)
 			return -ENOMEM;
 
 		nskb->vlan_tci = 0;