Input: add regulator haptic driver

Input: add regulator haptic driver

This change adds support for haptic driver controlled by voltage of a
regulator. Userspace can control the device via Force Feedback interface
from input framework.

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Signed-off-by: Hyunhee Kim <hyunhee.kim@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>