input: atmel_mxt_ts: disable/enable IRQ on suspend/resume.

Disable IRQ in suspend and enable IRQ in resume function
to remove the appearance of old touch data after suspend
and to fix the sticky touch problem.

CRs-Fixed: 526552
Change-Id: Ia6e7823a4a5615b2bc5209e8b3425b52827161de
Signed-off-by: Sarada Prasanna Garnayak <c_sgarna@codeaurora.org>