vxlan: simplify if clause in dev_close

Dan Carpenter's static checker warned that in vxlan_stop we are checking
if 'vs' can be NULL while later we simply derreference it.

As after commit 56ef9c90 ("vxlan: Move socket initialization to
within rtnl scope") 'vs' just cannot be NULL in vxlan_stop() anymore, as
the interface won't go up if the socket initialization fails. So we are
good to just remove the check and make it consistent.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -2254,7 +2254,7 @@ static int vxlan_stop(struct net_device *dev)
 	struct vxlan_sock *vs = vxlan->vn_sock;
 	int ret = 0;
 
-	if (vs && vxlan_addr_multicast(&vxlan->default_dst.remote_ip) &&
+	if (vxlan_addr_multicast(&vxlan->default_dst.remote_ip) &&
 	    !vxlan_group_used(vn, vxlan)) {
 		ret = vxlan_igmp_leave(vxlan);
 		if (ret)