drivers: eth: gmac: Fix MAC address info log
drivers: eth: gmac: Fix MAC address info log

Each MAC byte should be printed with the %02x format.

Signed-off-by: Tomasz Gorochowik <265c7c25eca9aa9127910457b0aea7e793d329f1@antmicro.com>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,nashif/zephyr,finikorg/zephyr,nashif/zephyr,nashif/zephyr,Vudentz/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,ldts/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,finikorg/zephyr,Vudentz/zephyr,ldts/zephyr