power: supply: rt5033_charger: Add RT5033 charger device driver

This patch adds device driver of Richtek RT5033 PMIC. The driver supports
switching charger. rt5033 charger provides three charging modes. The charging
modes are pre-charge mode, fast charge mode and constant voltage mode. They
vary in charge rate, the charge parameters can be controlled by i2c interface.

Tested-by: Raymond Hackley <raymondhackley@protonmail.com>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/9556d4ebb30fd321e37aa0eb343554122e4720c9.1684182964.git.jahau@rocketmail.com