qeth: add network device features for VLAN devices

Network device features indicate the capabilities of network devices (e.g.,
TX checksum offloading and TSO) and their configuration state. Additional
network device features (vlan_features) indicate for each network device,
which capabilities can be used on VLAN devices, that are configured on the
respective base network device.

In the current qeth implementation, network device features are only set
for the base network devices and not for the VLAN devices. Thus, features
like TX checksum offloading cannot be used on VLAN devices.

This patch adds network device features to vlan_features, so they can be
used by VLAN devices.

Signed-off-by: Hans Wippel <hwippel@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>