LoongArch: dts: Add new supported device nodes to Loongson-2K0500

By now, more Loongson-2K0500 related drivers are supported, such as
clock controller, thermal controller, and dma controller. So we add
these device nodes to the Loongson-2K0500 dts file.

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