LoongArch: dts: loongson-2k0500: Add default interrupt controller address cells

LoongArch: dts: loongson-2k0500: Add default interrupt controller address cells

Add missing address-cells 0 to the Local I/O and Extend I/O interrupt
controller node to silence W=1 warning:

  loongson-2k0500.dtsi:513.5-51: Warning (interrupt_map): /bus@10000000/pcie@1a000000/pcie@0,0:interrupt-map:
    Missing property '#address-cells' in node /bus@10000000/interrupt-controller@1fe11600, using 0 as fallback

Value '0' is correct because:
1. The Local I/O & Extend I/O interrupt controller do not have children,
2. interrupt-map property (in PCI node) consists of five components and
   the fourth component "parent unit address", which size is defined by
   '#address-cells' of the node pointed to by the interrupt-parent
   component, is not used (=0)

Cc: stable@vger.kernel.org
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>