media: dt-bindings: rockchip-vpu: Convert bindings to json-schema

Convert Rockchip VPU (Hantro IP block) codec driver documentation to
json-schema.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>