drivers: ethernet: stm32_hal: Move mac address configuration to dt

Deprecate Kconfig mac address related symbols and replace by existing
device tree properties:
- local-mac-address
- zephyr,random-mac-address

User who wants to keep using deprecating method of defining random
MAC address using Kconfig should set CONFIG_ETH_STM32_HAL_RANDOM_MAC=y.

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>