msm: kgsl: Wake up GPU only for touch events

Register the KGSL input event handler only for
touch input events to make sure input event handler
is called only for touch input events.

Change-Id: I68938fbbf870bd3bce83cb057b504674753d6de8
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>