ARM: dts: BCM5301X: Describe PCIe controllers fully

ARM: dts: BCM5301X: Describe PCIe controllers fully

Tested successfully on BCM47094 SoC using Linux's pcie-iproc-platform
driver.

This fixes:
arch/arm/boot/dts/broadcom/bcm4708-asus-rt-ac56u.dtb: pcie@12000: 'device_type' is a required property
        from schema $id: http://devicetree.org/schemas/pci/pci-bus.yaml#
arch/arm/boot/dts/broadcom/bcm4708-asus-rt-ac56u.dtb: pcie@12000: 'ranges' is a required property
        from schema $id: http://devicetree.org/schemas/pci/pci-bus.yaml#
arch/arm/boot/dts/broadcom/bcm4708-asus-rt-ac56u.dtb: pcie@13000: 'device_type' is a required property
        from schema $id: http://devicetree.org/schemas/pci/pci-bus.yaml#
arch/arm/boot/dts/broadcom/bcm4708-asus-rt-ac56u.dtb: pcie@13000: 'ranges' is a required property
        from schema $id: http://devicetree.org/schemas/pci/pci-bus.yaml#
arch/arm/boot/dts/broadcom/bcm4708-asus-rt-ac56u.dtb: pcie@14000: 'device_type' is a required property
        from schema $id: http://devicetree.org/schemas/pci/pci-bus.yaml#
arch/arm/boot/dts/broadcom/bcm4708-asus-rt-ac56u.dtb: pcie@14000: 'ranges' is a required property
        from schema $id: http://devicetree.org/schemas/pci/pci-bus.yaml#

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20260108224026.3550-1-zajec5@gmail.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>