thermal: intel: Adjust ops handling during thermal zone registration

Because thermal zone operations are now stored directly in struct
thermal_zone_device, thermal zone creators can discard the operations
structure after the zone registration is complete, or it can be made
read-only.

Accordingly, make int340x_thermal_zone_add() use a local variable to
represent thermal zone operations, so it is freed automatically upon the
function exit, and make the other Intel thermal drivers use const zone
operations structures.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>