arm64: dts: rockchip: Define the rockchip Video Decoder node on rk3399

RK3399 has a Video decoder, define the node in the dtsi. We also add
the missing power-domain in mmu node and enable the block.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Link: https://lore.kernel.org/r/20200403221345.16702-6-ezequiel@collabora.com


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