power: supply: pm2301_charger: Delete driver

The PM2301 was only used in tandem with AB9540, part of U9540,
a platform that was cancelled and never deployed in products.
Delete it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>