net: dpaa2-switch: call dpaa2_switch_port_disconnect_mac on probe error path

Currently when probing returns an error, the netdev is freed but
phylink_disconnect is not called.

Create a common function between the unbind path and the error path,
call it the opposite of dpaa2_switch_probe_port: dpaa2_switch_remove_port,
and call it from both the unbind and the error path.

Fixes: 84cba729

 ("dpaa2-switch: integrate the MAC endpoint support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>