vlan: Match underlying dev carrier on vlan add

When adding a new vlan, if the underlying interface has no carrier,
then the newly added vlan interface should also have no carrier.
At present, this is not true - the newly added vlan is added with
carrier up.  Fix by checking state of real device.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: David S. Miller <davem@davemloft.net>