via-velocity: Remove private device list

via-velocity maintains a list of its devices in order to determine
whether a netdev notification applies to one of them.  That can be
determined simply by checking the netdev_ops pointer, so the list can
be removed.

Compile-tested only.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>