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

Optional properties:
- clock-names		: Should be  "s_axi_aclk"
- clocks		: Input clock specifier. Refer to common clock bindings.

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