thermal/thresholds: Fix boundaries and detection routine

The current implementation does not work if the thermal zone is
interrupt driven only.

The boundaries are not correctly checked and computed as it happens
only when the temperature is increasing or decreasing.

The problem arises because the routine to detect when we cross a
threshold is correlated with the computation of the boundaries. We
assume we have to recompute the boundaries when a threshold is crossed
but actually we should do that even if the it is not the case.

Mixing the boundaries computation and the threshold detection for the
sake of optimizing the routine is much more complex as it appears
intuitively and prone to errors.

This fix separates the boundaries computation and the threshold
crossing detection into different routines. The result is a code much
more simple to understand, thus easier to maintain.

The drawback is we browse the thresholds list several time but we can
consider that as neglictible because that happens when the temperature
is updated. There are certainly some aeras to improve in the
temperature update routine but it would be not adequate as this change
aims to fix the thresholds for v6.13.

Fixes: 445936f9 ("thermal: core: Add user thresholds support")
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org> # rock5b, Lenovo x13s
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20241216212644.1145122-1-daniel.lezcano@linaro.org


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>