power: supply: ab8500: Make recharge capacity a constant

The recharge capacity is the hysteresis level for a charger to
restart when a battery does not support maintenance charging.

All products using the AB8500 have batteries supporting
maintenace charging and all code has always set this to 95%.

Turn it into a constant.

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