dt-bindings: input: convert cros-ec-keyb to json-schema

Convert the google,cros-ec-keyb binding to YAML and add it as a property
of google,cros-ec.yaml

Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Ricardo Cañuelo <ricardo.canuelo@collabora.com>
Link: https://lore.kernel.org/r/20201021114308.25485-3-ricardo.canuelo@collabora.com


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