vlan: correct the file path in vlan_dev_change_flags() comment

The vlan_flags enum is defined in include/uapi/linux/if_vlan.h file.
not in include/linux/if_vlan.h file.
Signed-off-by: Sun Lianwen <sunlw.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/8021q/vlan_dev.c

@@ -215,7 +215,9 @@ int vlan_dev_set_egress_priority(const struct net_device *dev,
 	return 0;
 }
 
-/* Flags are defined in the vlan_flags enum in include/linux/if_vlan.h file. */
+/* Flags are defined in the vlan_flags enum in
+ * include/uapi/linux/if_vlan.h file.
+ */
 int vlan_dev_change_flags(const struct net_device *dev, u32 flags, u32 mask)
 {
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);