Add the Video Processing Unit node for RK3288 SoC.

Fix the VPU IOMMU node, which was disabled and lacking
its power domain property.
Reviewed-by: NTomasz Figa <tfiga@chromium.org>
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>