net: vlan: fix nlmsg size calculation in vlan_get_size()

This patch fixes the calculation of the nlmsg size, by adding the missing
nla_total_size().

Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/8021q/vlan_netlink.c

@@ -171,7 +171,7 @@ static size_t vlan_get_size(const struct net_device *dev)
 
 	return nla_total_size(2) +	/* IFLA_VLAN_PROTOCOL */
 	       nla_total_size(2) +	/* IFLA_VLAN_ID */
-	       sizeof(struct ifla_vlan_flags) + /* IFLA_VLAN_FLAGS */
+	       nla_total_size(sizeof(struct ifla_vlan_flags)) + /* IFLA_VLAN_FLAGS */
 	       vlan_qos_map_size(vlan->nr_ingress_mappings) +
 	       vlan_qos_map_size(vlan->nr_egress_mappings);
 }