Make the acerhdf driver use the .should_bind() thermal zone
callback to provide the thermal core with the information on whether or
not to bind the given cooling device to the given trip point in the
given thermal zone.  If it returns 'true', the thermal core will bind
the cooling device to the trip and the corresponding unbinding will be
taken care of automatically by the core on the removal of the involved
thermal zone or cooling device.

The previously existing acerhdf_bind() function bound cooling devices
to thermal trip point 0 only, so the new callback needs to return 'true'
for trip point 0.  However, it is straightforward to observe that trip
point 0 is an active trip point and the only other trip point in the
driver's thermal zone is a critical one, so it is sufficient to return
'true' from that callback if the type of the given trip point is
THERMAL_TRIP_ACTIVE.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Peter Kästle <peter@piie.net>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/3779411.MHq7AAxBmi@rjwysocki.net