Device tree bindings for GPMC connected OneNANDs

GPMC connected OneNAND (found on OMAP boards) are represented as child nodes of
the GPMC controller with a name of "onenand".

All timing relevant properties as well as generic gpmc child properties are
explained in a separate documents - please refer to
Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt

Required properties:

 - compatible:		"ti,omap2-onenand"
 - reg:			The CS line the peripheral is connected to
 - gpmc,device-width:	Width of the ONENAND device connected to the GPMC
			in bytes. Must be 1 or 2.

Optional properties:

 - int-gpios:		GPIO specifier for the INT pin.

For inline partition table parsing (optional):

 - #address-cells: should be set to 1
 - #size-cells: should be set to 1

Example for an OMAP3430 board:

	gpmc: gpmc@6e000000 {
		compatible = "ti,omap3430-gpmc";
		ti,hwmods = "gpmc";
		reg = <0x6e000000 0x1000000>;
		interrupts = <20>;
		gpmc,num-cs = <8>;
		gpmc,num-waitpins = <4>;
		#address-cells = <2>;
		#size-cells = <1>;

		onenand@0 {
			compatible = "ti,omap2-onenand";
			reg = <0 0 0>; /* CS0, offset 0 */
			gpmc,device-width = <2>;

			#address-cells = <1>;
			#size-cells = <1>;

			/* partitions go here */
		};
	};