Hisilicon Hi6220 GPIO controller bindings

Required properties:
	- compatible: "arm,pl061","arm,primecell"
	- gpio-controller: Marks the device node as a GPIO controller.
	- #gpio-cells: Should be 2. See gpio.txt in this directory for a
		 description of	the cells format.
	- interrupt-controller: Mark the device node as an interrupt controller

Example:

	gpio0: gpio@f8011000 {
		compatible = "arm,pl061", "arm,primecell";
		reg = <0x0 0xf8011000 0x0 0x1000>;
		interrupts = <0	52 0x4>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
		clocks = <&ao_ctrl 2>;
		clock-names = "apb_pclk";
		status = "ok";
	};
