net: aquantia: driver should correctly declare vlan_features bits

In particular, not reporting SG forced skbs to be linear for vlan
interfaces over atlantic NIC.

With this fix it is possible to enable SG feature on device and
therefore optimize performance.

Reported-by: Ma Yuying <yuma@redhat.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>