net: dsa: microchip: add config_cpu_port to struct ksz_dev_ops

To have the common set of initialization in ksz_setup, introduced the
new config_cpu_port member to ksz_dev_ops. Since both the ksz8795.c and
ksz9477.c configuring the cpu port in the setup function, introduced the
member.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>