Input: atmel_mxt_ts - Fix calls to mxt_check_retrigen

We must check whether the RETRIGEN workaround is necessary before the IRQ is
first acquired on probe, and if the configuration is changed.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Signed-off-by: Atul Tiwari <atul.tiwari@atmel.com>
Input: atmel_mxt_ts - Fix bugs in config upgrade

Address a couple of bugs in the handling of objects in the config file which
are different lengths to on the chip.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Signed-off-by: Atul Tiwari <atul.tiwari@atmel.com>
Input: atmel_mxt_ts - Only warn when config CRC does not match

The CRC will not match if the config has been upgraded (ie the info_crc
doesn't match), also there are new chips with objects included in the CRC
which are previous to T7, and some chips without T7, which means that this
code must only produce a warning until those issues are dealt with.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Signed-off-by: Atul Tiwari <atul.tiwari@atmel.com>