input: touchscreen: add option to ignore Focaltech family-id check

Focaltech touchscreen ICs may use different chip IDs for same module.
Add support to ignore ID check for such cases.

This patch is propagated from msm-3.10 kernel
'commit d6e831bdf2af ("input: touchscreen: add option to ignore
Focaltech family-id check")'

Also fix the checkpatch errors.

Change-Id: I0fe8da6a5e687317b4878b59ac5d1a4a4b620e1d
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>
Signed-off-by: Sudhakar Manapati <smanap@codeaurora.org>