dt-bindings: power: supply: Add bindings for Microchip UCS1002

Add bindings for Microchip UCS1002 Programmable USB Port Power
Controller with Charger Emulation.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Rob Herring <robh+dt@kernel.org>
Cc: Enric Balletbo Serra <enric.balletbo@collabora.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>