input: synaptics_dsx_fw_update: modify firmware upgrade procedure

Modify the firmware upgrade procedure based on the following requirements:

If config id of the firmware file is greater than the config id in the
device and if packrat id of the firmware img file is greater than the
firmware build id in the device, then during the firmware upgrade
procedure, both firmware and config areas are upgraded. Otherwise,
if the packrat id of the firmware img file is equal to the firmware
build id in the device, then only the config area is upgraded. However,
if the packrat id of the firmware img file is lesser than the firmware
build id in the device, then it is considered as an error.

Similarly, if config id of the firmware file is equal to the config id
in the device and if packrat id of the firmware img file is greater than
the firmware build id in the device, then during the firmware upgrade
procedure, both firmware and config areas are upgraded. Otherwise, if
the packrat id of the firmware img file is equal to the firmware build
id in the device, then no upgrade is needed. However, if the packrat id
of the firmware img file is lesser than the firmware build id in the
device, then it is considered as an error.

This is a propagated patch from 3.10 kernel
commit - d9921ff0ce4024b43837d794cc261b52ae58f776 ,
input: synaptics_dsx_fw_update: modify firmware upgrade procedure

Change-Id: I646d2c04243a30b77d48698cce76e9e183bd6db1
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>