power: supply: collie_battery: Convert to GPIO descriptors

This converts the Collie battery driver to use GPIO descriptors.
We use a mixture of 3 GPIOs defined in the machine and 3
GPIOs requested directly from the ucb1x00 chip.

Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>