thermal/drivers/mediatek/lvts: Disable Stage 3 thermal threshold

thermal/drivers/mediatek/lvts: Disable Stage 3 thermal threshold

commit c612cbcdf603aefb3358b2e3964dcd5aa3f827a0 upstream.

The Stage 3 thermal threshold is currently configured during
the controller initialization to 105 Celsius. From the kernel
perspective, this configuration is harmful because:
* The stage 3 interrupt that gets triggered when the threshold is
  crossed is not handled in any way by the IRQ handler, it just gets
  cleared. Besides, the temperature used for stage 3 comes from the
  sensors, and the critical thermal trip points described in the
  Devicetree will already cause a shutdown when crossed (at a lower
  temperature, of 100 Celsius, for all SoCs currently using this
  driver).
* The only effect of crossing the stage 3 threshold that has been
  observed is that it causes the machine to no longer be able to enter
  suspend. Even if that was a result of a momentary glitch in the
  temperature reading of a sensor (as has been observed on the
  MT8192-based Chromebooks).

For those reasons, disable the Stage 3 thermal threshold configuration.

Cc: stable@vger.kernel.org
Reported-by: Hsin-Te Yuan <yuanhsinte@chromium.org>
Closes: https://lore.kernel.org/all/20241108-lvts-v1-1-eee339c6ca20@chromium.org/
Fixes: f5f633b18234 ("thermal/drivers/mediatek: Add the Low Voltage Thermal Sensor driver")
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20250113-mt8192-lvts-filtered-suspend-fix-v2-2-07a25200c7c6@collabora.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>