hw/loongarch: Add platform bus support

Add platform bus support and add the bus information such as address,
size, irq number to FDT table.

Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Acked-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20220908094623.73051-5-yangxiaojuan@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
4 files changed