mfd: max77843: Add max77843 MFD driver core driver

This patch adds MAX77843 core/irq driver to support PMIC,
MUIC(Micro USB Interface Controller), Charger, Fuel Gauge,
LED and Haptic device.

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Signed-off-by: Beomho Seo <beomho.seo@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>