extcon: MAX77693: Add extcon-max77693 driver to support Maxim MAX77693 MUIC device

This patch support Maxim MAX77693 MUIC device by using EXTCON Subsystem
to handle various external connector. The extcon-max77693 use regmap
method for i2c communication and support irq domain instead of previous
method of irq base.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>