input: touchscreen: correct probe error path for ITE tech driver

ITE tech touch driver dynamically detects the controller attached
to the device in its probe. And if the driver fails to identify
the controller, it exits the probe with the error code. But in the
probe error path, it doesn't retain the error code, replace it
with zero and registers the device instead of failing.
This change corrects the probe error path of ITE tech touch driver
and makes sure it returns the error code if it fails.

Change-Id: I8f193ee10076b6cf058b0a6940db54f71f70b758
Signed-off-by: Shantanu Jain <shjain@codeaurora.org>