qbt: Add support for touch based finger detect

Register for notification from touchscreen driver
whenever any touch event occurs in the area of
interest. Filter the touch events by distance
moved and add them to the event queue.

Change-Id: Iaf6caaaf9aea95441cbcfa41cf15d9685b8357a1
Signed-off-by: Abir Ghosh <abirg@codeaurora.org>