Xilinx USB2 device controller

Required properties:
- compatible		: Should be "xlnx,usb2-device-4.00.a"
- reg			: Physical base address and size of the USB2
			  device registers map.
- interrupts		: Should contain single irq line of USB2 device
			  controller
- xlnx,has-builtin-dma	: if DMA is included

Example:
 		axi-usb2-device@42e00000 {
                        compatible = "xlnx,usb2-device-4.00.a";
                        interrupts = <0x0 0x39 0x1>;
                        reg = <0x42e00000 0x10000>;
                        xlnx,has-builtin-dma;
                };

