dt-bindings: adv7180: Convert bindings to json-schema

Convert ADV7180 analog video decoder documentation to json-schema.

As the examples in the bindings can be tested add another example to
test the more advance adv7180cp binding description.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20200704160644.3040636-2-niklas.soderlund+renesas@ragnatech.se


Signed-off-by: Rob Herring <robh@kernel.org>