power: supply: gpio-charger: add support for default charge current limit

power: supply: gpio-charger: add support for default charge current limit

With DT properties charge-current-limit-gpios and
charge-current-limit-mapping one can define charge current limits in uA
using up to 32 GPIOs. At the moment the driver defaults to smallest charge
current limitation for safety reasons. When disabling charging is
supported, which should be common, the driver defaults to non charging on
probe. By having a default, charging can be enabled on probe for such
devices.

Signed-off-by: Dimitri Fedrau <dimitri.fedrau@liebherr.com>
Link: https://lore.kernel.org/r/20241218-default-charge-current-limit-v3-2-b26118cf06b5@liebherr.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>