Input: atmel_mxt_ts - download device config using firmware loader

The existing implementation which encodes the configuration as a binary
blob in platform data is unsatisfactory since it requires a kernel
recompile for the configuration to be changed, and it doesn't deal well
with firmware changes that move values around on the chip.

Atmel define an ASCII format for the configuration which can be exported
from their tools. This patch implements a parser for that format which
loads the configuration via the firmware loader and sends it to the MXT
chip.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>