regulator: max14577: Add regulator driver for Maxim 14577

regulator: max14577: Add regulator driver for Maxim 14577

MAX14577 chip is a multi-function device which includes MUIC,
charger and voltage regulator. The driver is located in drivers/mfd.

This patch adds regulator driver for MAX14577 chip. There are two
regulators in this chip:
1. Safeout LDO with constant voltage output of 4.9V. It can be only
   enabled or disabled.
2. Current regulator for the charger. It provides current from 90mA up
   to 950mA.
Driver supports Device Tree.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>