LoongArch: dts: Describe PCI sideband IRQ through interrupt-extended

LoongArch: dts: Describe PCI sideband IRQ through interrupt-extended

SoC integrated peripherals on LS2K1000 and LS2K2000 could be discovered
as PCI devices, but require sideband interrupts to function, which are
previously described by interrupts and interrupt-parent properties.

However, pci/pci-device.yaml allows interrupts property to only specify
PCI INTx interrupts, not sideband ones. Convert these devices to use
interrupt-extended property, which describes sideband interrupts used by
PCI devices since dt-schema commit e6ea659d2baa ("schemas: pci-device:
Allow interrupts-extended for sideband interrupts"), eliminating
dtbs_check warnings.

Cc: stable@vger.kernel.org
Fixes: 30a5532a3206 ("LoongArch: dts: DeviceTree for Loongson-2K1000")
Signed-off-by: Yao Zi <me@ziyao.cc>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>