mfd: Add platform data and devices for MAX8997 LED control

MAX8997 device does not support LED control function of it.
To enable MAX8997-LED driver, platform data and devices for LED are updated.

Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>