ARM: zynq: dts: Added alias for usb node

This patch added alias for usb node in dts file.

Signed-off-by: Vipul Kumar <vipul.kumar@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/dts/zynq-zc702.dts

@@ -16,6 +16,7 @@
 		serial0 = &uart1;
 		spi0 = &qspi;
 		mmc0 = &sdhci0;
+		usb0 = &usb0;
 	};
 
 	memory@0 {