ARM: dts: BCM5301X: Add cells sizes to PCIe nodes

This fixes:
arch/arm/boot/dts/bcm4708-asus-rt-ac56u.dtb: pcie@12000: '#address-cells' is a required property
        From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
arch/arm/boot/dts/bcm4708-asus-rt-ac56u.dtb: pcie@12000: '#size-cells' is a required property
        From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
arch/arm/boot/dts/bcm4708-asus-rt-ac56u.dtb: pcie@13000: '#address-cells' is a required property
        From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
arch/arm/boot/dts/bcm4708-asus-rt-ac56u.dtb: pcie@13000: '#size-cells' is a required property
        From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
arch/arm/boot/dts/bcm4708-asus-rt-ac56u.dtb: pcie@14000: '#address-cells' is a required property
        From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
arch/arm/boot/dts/bcm4708-asus-rt-ac56u.dtb: pcie@14000: '#size-cells' is a required property
        From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml

Two properties that need to be added later are "device_type" and
"ranges". Adding "device_type" on its own causes a new warning and the
value of "ranges" needs to be determined yet.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20230616105827.21656-1-zajec5@gmail.com


Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>