dt-bindings: display: convert rockchip vop bindings to yaml

Current dts files with 'vop' nodes are manually verified.
In order to automate this process rockchip-vop.txt
has to be converted to yaml.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200403142235.8870-1-jbx6244@gmail.com