The libretech-ac aka aml-s805x-ac supports mainline U-boot
from a dedicated SPI flash, move the board support into
a dedicated vendor/board subdirectory in order to support
vendor specific customization.
It also aligns with the vendor downstream changes.
Link: https://lore.kernel.org/r/20240917-u-boot-topic-dynamic-uuid-v2-1-416e39c6e271@linaro.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
