net: vlan: sync VLAN features with lower device

After registering a VLAN device and setting its feature flags, we need to
synchronize the VLAN features with the lower device. For example, the VLAN
device does not have the NETIF_F_LRO flag, it should be synchronized with
the lower device based on the NETIF_F_UPPER_DISABLES definition.

As the dev->vlan_features has changed, we need to call
netdev_update_features(). The caller must run after netdev_upper_dev_link()
links the lower devices, so this patch adds the netdev_update_features()
call in register_vlan_dev().

Fixes: fd867d51f889 ("net/core: generic support for disabling netdev features down stack")
Signed-off-by: Hangbin Liu <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/8021q/vlan.c

···
 	vlan_group_set_device(grp, vlan->vlan_proto, vlan_id, dev);
 	grp->nr_vlan_devs++;
 
+	netdev_update_features(dev);
+
 	return 0;
 
 out_unregister_netdev: