thermal/drivers/mediatek/lvts_thermal: Disable undesired interrupts

Out of the many interrupts supported by the hardware, the only ones of
interest to the driver currently are:
* The temperature went over the high offset threshold, for any of the
  sensors
* The temperature went below the low offset threshold, for any of the
  sensors
* The temperature went over the stage3 threshold

These are the only thresholds configured by the driver through the
OFFSETH, OFFSETL, and PROTTC registers, respectively.

The current interrupt mask in LVTS_MONINT_CONF, enables many more
interrupts, including data ready on sensors for both filtered and
immediate mode. These are not only not handled by the driver, but they
are also triggered too often, causing unneeded overhead. Disable these
unnecessary interrupts.

The meaning of each bit can be seen in the comment describing
LVTS_MONINTST in the IRQ handler.

Fixes: f5f633b1 ("thermal/drivers/mediatek: Add the Low Voltage Thermal Sensor driver")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230706153823.201943-5-nfraprado@collabora.com