NAND support for Marvell Orion SoC platforms

Required properties:
- compatible : "marvell,orion-nand".
- reg : Base physical address of the NAND and length of memory mapped
	region

Optional properties:
- cle : Address line number connected to CLE. Default is 0
- ale : Address line number connected to ALE. Default is 1
- bank-width : Width in bytes of the device. Default is 1
- chip-delay : Chip dependent delay for transferring data from array to read
               registers in usecs

The device tree may optionally contain sub-nodes describing partitions of the
address space. See mtd.yaml for more detail.

Example:

nand@f4000000 {
	#address-cells = <1>;
	#size-cells = <1>;
	cle = <0>;
	ale = <1>;
	bank-width = <1>;
	chip-delay = <25>;
	compatible = "marvell,orion-nand";
	reg = <0xf4000000 0x400>;

	partition@0 {
		label = "u-boot";
		reg = <0x0000000 0x100000>;
		read-only;
	};

	partition@100000 {
		label = "uImage";
		reg = <0x0100000 0x200000>;
	};

	partition@300000 {
		label = "dtb";
		reg = <0x0300000 0x100000>;
	};

	partition@400000 {
		label = "root";
		reg = <0x0400000 0x7d00000>;
	};
};