Add initial support for the libretech aml-s905x-cc (Le Potato) v2

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200915141921.57258-3-jbrunet@baylibre.com