powerpc/dts/virtex440: Declare address/size-cells for phy device

This fixes a warning:

DTC arch/powerpc/boot/virtex440-ml507.dtb
Warning (reg_format): "reg" property in /plb@0/xps-ll-temac@81c00000/ethernet@81c00000/phy@7 has invalid length (4 bytes) (#address-cells == 2, #size-cells == 1)
Warning (avoid_default_addr_size): Relying on default #address-cells value for /plb@0/xps-ll-temac@81c00000/ethernet@81c00000/phy@7
Warning (avoid_default_addr_size): Relying on default #size-cells value for /plb@0/xps-ll-temac@81c00000/ethernet@81c00000/phy@7

Signed-off-by: Ian Campbell <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Gernot Vormayr <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/boot/dts/virtex440-ml507.dts

···
 			#size-cells = <1>;
 			compatible = "xlnx,compound";
 			ethernet@81c00000 {
+				#address-cells = <1>;
+				#size-cells = <0>;
 				compatible = "xlnx,xps-ll-temac-1.01.b";
 				device_type = "network";
 				interrupt-parent = <&xps_intc_0>;