drivers: ethernet: stm32: remove deprecated MAC address Kconfigs

The following Kconfigs:

- `CONFIG_ETH_STM32_HAL_RANDOM_MAC`
- `CONFIG_ETH_STM32_HAL_USER_STATIC_MAC`
- `CONFIG_ETH_STM32_HAL_MAC3`
- `CONFIG_ETH_STM32_HAL_MAC4`
- `CONFIG_ETH_STM32_HAL_MAC5`

have been deprecated for more than 2 releases, user should
have switched to the devicetree method now, remove them.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>