CHROMIUM: Input: atmel_mxt_ts - verify info block checksum

CHROMIUM: Input: atmel_mxt_ts - verify info block checksum

Compute 24 bit CRC over entire Information Block (ID info plus Object
Table), and verify that it matches checksum read from the device.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
BUG=chrome-os-partner:9103
TEST=Verify atmel device is discovered and operates as before.

Change-Id: Ic20f585abf6726e7ff5e2cc4afd7ae805180b81d
Reviewed-on: https://gerrit.chromium.org/gerrit/20600
Commit-Ready: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Daniel Kurtz <djkurtz@chromium.org>