thermal/drivers/loongson-2: Add thermal management support

This patch adds the support for Loongson-2 thermal sensor controller,
which can support maximum four sensor selectors that corresponding to four
sets of thermal control registers and one set of sampling register. The
sensor selector can selector a speific thermal sensor as temperature input.
The sampling register is used to obtain the temperature in real time, the
control register GATE field is used to set the threshold of high or low
temperature, when the input temperature is higher than the high temperature
threshold or lower than the low temperature threshold, an interrupt will
occur.

Signed-off-by: zhanghongchen <zhanghongchen@loongson.cn>
Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230817021007.10350-1-zhuyinbo@loongson.cn