power: supply: max14656: Drop unused includes

The driver includes two GPIO headers but does not use
symbols from any of them, so drop these includes.

Cc: Alexander Kurz <akurz@blala.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>