input: it7258_ts_i2c: add low power mode support in suspend state

Add low power idle mode support in suspend state for ITE tech
touchscreen driver.
Also, execute the touch to wake feature code only when device moves
from idle state to active state.

Change-Id: Ia989d8130bbded4ae5acab0b9c3122998acb2056
Signed-off-by: Shantanu Jain <shjain@codeaurora.org>