Register for extcon notification and set charging current depending on
the detected cable type. Current values are taken from vendor kernel,
where most charger types end up setting 650mA [0].

Also enable and disable the CHARGER regulator based on extcon events.

[0] https://github.com/krzk/linux-vendor-backup/blob/samsung/galaxy-s2-epic-4g-touch-sph-d710-exynos4210-dump/drivers/misc/max8997-muic.c#L1675-L1678Signed-off-by: Timon Baetz <timon.baetz@protonmail.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>