arm64: xilinx: Remove address/size-cells from gem nodes

arm64: xilinx: Remove address/size-cells from gem nodes

Some boards are using one mdio bus which holds multiple phys and also
boards are using mdio node for bus description. That's why there are cases
where address/size-cells are unnecessary which is also reported by make W=1
dtbs. That's why remove them from zynqmp.dtsi and let board DTSes to handle
it based on used description.

Error log:
/axi/ethernet@ff0e0000: unnecessary #address-cells/#size-cells without
"ranges" or child "reg" property

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/7252203d52af3ca8867764c8514affc4828e530d.1695040866.git.michal.simek@amd.com