mvebu: fix usb node dtc warnings for Ctera C200 V2

mvebu: fix usb node dtc warnings for Ctera C200 V2

Correct #address-cells and #size-cells based on child node reg
property structure to fix the following dtc warnings:

armada-370-c200-v2.dts:342.6-16: Warning (reg_format): /soc/pcie@82000000/pcie@1,0/bridge@0,1/usb@1,0/port@1:reg: property has invalid length (4 bytes) (#address-cells == 3, #size-cells == 2)
armada-370-c200-v2.dts:347.6-16: Warning (reg_format): /soc/pcie@82000000/pcie@1,0/bridge@0,1/usb@1,0/port@2:reg: property has invalid length (4 bytes) (#address-cells == 3, #size-cells == 2)

Signed-off-by: Shiji Yang <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18242
Signed-off-by: Hauke Mehrtens <[email protected]>