dt-bindings: arm: amlogic: add ODROID-HC4 bindings

Add the board bindings for the ODROID-HC4 device.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20210202021021.11068-5-christianshewitt@gmail.com