Input: atmel_mxt_ts: Update config to newer version only

Add version checking so that config update only occurs when the config
data supplied in the platform data is of newer version. If the
controller is previously programmed with wrong version of config data,
based on controller type and firmware version, the driver will program
the latest config data present in the platform data to the controller.

Change-Id: I286852533aef920accb254ab7259edc144357dd3
Signed-off-by: Jing Lin <jinglin@codeaurora.org>