board: amlogic: add meson_generate_serial_ethaddr fallback to p200

Add a fall-back method to generate ethaddr from CPU serial on p200 boards
if the MAC cannot be read from efuse. This prevents random MAC addresses
on the WeTek Hub/Play2 boards.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Link: https://lore.kernel.org/r/20240324151905.3817732-3-christianshewitt@gmail.com


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>