net: dsa: ksz8794: Remove check for CPU port in the switch setup
net: dsa: ksz8794: Remove check for CPU port in the switch setup

The check for CPU port on the KSZ8794 when the switch is initialized,
is not required as the last port number is always smaller than the CPU
port.

Signed-off-by: Lukasz Majewski <7acbb0643e3da1a0f6f894ebd720fb3807e67dff@denx.de>

galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr