In order to reduce code duplication, merge update_passive_devices() and
update_active_devices() into one function called update_trip_devices()
that will be used for updating both the passive and active trip points.

No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>