thermal/core: Compute low and high boundaries in thermal_zone_device_update()

thermal/core: Compute low and high boundaries in thermal_zone_device_update()

In order to set the scene for the thresholds support which have to
manipulate the low and high temperature boundaries for the interrupt
support, we must pass the low and high values to the incoming
thresholds routine.

The variables are set from the thermal_zone_set_trips() where the
function loops the thermal trips to figure out the next and the
previous temperatures to set the interrupt to be triggered when they
are crossed.

These variables will be needed by the function in charge of handling
the thresholds in the incoming changes but they are local to the
aforementioned function thermal_zone_set_trips().

Move the low and high boundaries computation out of the function in
thermal_zone_device_update() so they are accessible from there.

The positive side effect is they are computed in the same loop as
handle_thermal_trip(), so we remove one loop.

Co-developed-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20240816081241.1925221-2-daniel.lezcano@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>