Binding for Xilinx Uartlite Controller

Required properties:
- compatible : should be "xlnx,xps-uartlite-1.00.a", or "xlnx,opb-uartlite-1.00.b"
- reg: Should contain UART controller registers location and length.
- interrupts: Should contain UART controller interrupts.

Example:
	serial@40600000 {
		compatible = "xlnx,xps-uartlite-1.00.a";
		interrupts = <1 0>;
		reg = <0x40600000 0x10000>;
	};