rocker: Remove support for bypass bridge port attributes/vlan set

The bridge port attributes/vlan for mlxsw devices should be set only
from bridge code. The vlans are synced totally with the bridge so
there is no need to special dump support.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>