[VLAN]: Fix early vlan adding leads to not functional device

OK, I can see what's happening here. eth0 doesn't detect link-up until
after a few seconds, so when the vlan interface is opened immediately
after eth0 has been opened, it inherits the link-down state. Subsequently
the vlan interface is never properly activated and are thus unable to
transmit any packets.

dev->state bits are not supposed to be manipulated directly. Something
similar is probably needed for the netif_device_present() bit, although
I don't know how this is meant to work for a virtual device.

Signed-off-by: David S. Miller <[e-mail]>

net/8021q/vlan.c

···
 			if (!vlandev)
 				continue;
 
+			if (netif_carrier_ok(dev)) {
+				if (!netif_carrier_ok(vlandev))
+					netif_carrier_on(vlandev);
+			} else {
+				if (netif_carrier_ok(vlandev))
+					netif_carrier_off(vlandev);
+			}
+
 			if ((vlandev->state & VLAN_LINK_STATE_MASK) != flgs) {
 				vlandev->state = (vlandev->state &~ VLAN_LINK_STATE_MASK) 
 					| flgs;