net: dsa: microchip: ksz8795: update the port_cnt value in ksz_chip_data

The port_cnt value in the structure is not used in the switch_init.
Instead it uses the fls(chip->cpu_port), this is due to one of port in
the ksz8794 unavailable. The cpu_port for the 8794 is 0x10, fls(0x10) =
5, hence updating it directly in the ksz_chip_data structure in order to
same with all the other switches in ksz8795.c and ksz9477.c files.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>