dt-bindings: ARM: rockchip: Add Beelink A1

Add a binding for the RK3328-based Beelink A1 TV box.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/82324d17b770fa8ea189fa708490d2c8c0c9290e.1571090991.git.robin.murphy@arm.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>