Convert Renesas R-Car VIN bindings documentation to json-schema.

As the examples in the bindings now can be tested add a new one which
describes how the both a parallel and a CSI-2 source can be connected on
Gen3 SoCs.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Rob Herring <robh@kernel.org>