Allwinner A10 DMA Controller

This driver follows the generic DMA bindings defined in dma.txt.

Required properties:

- compatible:	Must be "allwinner,sun4i-a10-dma"
- reg:		Should contain the registers base address and length
- interrupts:	Should contain a reference to the interrupt used by this device
- clocks:	Should contain a reference to the parent AHB clock
- #dma-cells :	Should be 2, first cell denoting normal or dedicated dma,
		second cell holding the request line number.

Example:
	dma: dma-controller@01c02000 {
		compatible = "allwinner,sun4i-a10-dma";
		reg = <0x01c02000 0x1000>;
		interrupts = <27>;
		clocks = <&ahb_gates 6>;
		#dma-cells = <2>;
	};

Clients:

DMA clients connected to the Allwinner A10 DMA controller must use the
format described in the dma.txt file, using a three-cell specifier for
each channel: a phandle plus two integer cells.
The three cells in order are:

1. A phandle pointing to the DMA controller.
2. Whether it is using normal (0) or dedicated (1) channels
3. The port ID as specified in the datasheet

Example:
	spi2: spi@01c17000 {
		compatible = "allwinner,sun4i-a10-spi";
		reg = <0x01c17000 0x1000>;
		interrupts = <0 12 4>;
		clocks = <&ahb_gates 22>, <&spi2_clk>;
		clock-names = "ahb", "mod";
		dmas = <&dma 1 29>, <&dma 1 28>;
		dma-names = "rx", "tx";
		#address-cells = <1>;
		#size-cells = <0>;
	};
