This patch adds to tmp102 temperature sensor the possibility
to expose itself as thermal zone device, registered on the
thermal framework.
The thermal zone is built only if a device tree node
describing a thermal zone for this sensor is present
inside the tmp102 DT node. Otherwise, the driver behavior
will be the same.
Note: This patch has also been reviewed by Jean D. He has
requested to perform a wider inspection of possible
users of thermal and hwmon interaction API. On the other
hand, the change on this patch is acceptable on first
step of overall code change.