dt-bindings: arm: amlogic: add support for the Beelink GT-King Pro

The Shenzen AZW (Beelink) GT-King Pro is based on the Amlogic W400 reference
board with an S922X chip.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200520014329.12469-5-christianshewitt@gmail.com