* Freescale i.MX/MXC GPIO controller

Required properties:
- compatible : Should be "fsl,<soc>-gpio"
- reg : Address and length of the register set for the device
- interrupts : Should be the port interrupt shared by all 32 pins, if
  one number.  If two numbers, the first one is the interrupt shared
  by low 16 pins and the second one is for high 16 pins.
- gpio-controller : Marks the device node as a gpio controller.
- #gpio-cells : Should be two.  The first cell is the pin number and
  the second cell is used to specify optional parameters (currently
  unused).

Example:

gpio0: gpio@73f84000 {
	compatible = "fsl,imx51-gpio", "fsl,imx31-gpio";
	reg = <0x73f84000 0x4000>;
	interrupts = <50 51>;
	gpio-controller;
	#gpio-cells = <2>;
};