LoongArch: dts: Add new supported device nodes to Loongson-2K2000

By now, more Loongson-2K2000 related drivers are supported, such as
clock controller and thermal controller. So we add these device nodes
to the Loongson-2K2000 dts file.

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>