modify the device to enable to get the state as slide-open/slide-close.

This modify is for the devices which have a slidable H/W keyboard with backlight.

For example of current issues:
 - Backlight of H/W keyboard doesn't turn on when the device starts up with slide-open.
 - Home screen doesn't display with proper orientation when the device starts up with slide-open.

Change-Id: I6a6a18d0b09d0ba484ca992c9fb34f24de9bf21b