input: atmel_mxt: Add touch controller state check to enable IRQ

Touch controller requires enabling IRQ from suspend to wake.
Unpaired enable-disable will cause issues from kernel.

CRs-Fixed: 523607
Change-Id: Ia44e440a2ad05cd60b685714a15828916ca81e7e
Signed-off-by: Chun Zhang <chunz@codeaurora.org>