input: atmel_maxtouch_ts: add support for force cfg update

Add sysfs interface for configuration update. As part
of configuration update resolution can be changed. So,
add interfaces to update the resolution to the display.
Refactor the code to be efficient with this usecase.

Change-Id: I529108eec21dd4505cbf3dd87e879217eb718b55
Signed-off-by: Mohan Pallaka <mpallaka@codeaurora.org>