dt-bindings: touchscreen: Convert resistive-adc-touch binding to json schema

Convert the resistive-adc-touch binding to DT schema format using json-schema.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20210525054634.9134-2-o.rempel@pengutronix.de


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>