* Atmel Extensible Direct Memory Access Controller (XDMAC)

Required properties:
- compatible: Should be "atmel,<chip>-dma".
- reg: Should contain DMA registers location and length.
- interrupts: Should contain DMA interrupt.
- #dma-cells: Must be <2>, used to represent the number of integer cells in
the dmas property of client devices.

Example:

dma1: dma-controller@f0004000 {
	compatible = "atmel,sama5d4-dma";
	reg = <0xf0004000 0x200>;
	interrupts = <50 4 0>;
	#dma-cells = <2>;
};

DMA clients connected to the Atmel XDMA 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 two cells in order are:

1. A phandle pointing to the DMA controller.
2. The memory interface (16 most significant bits), the peripheral interface
(16 less significant bits).
3. Channel configuration register. Configurable fields are:
  - bit 30-24: PERID, peripheral identifier.

Example:

i2c2: i2c@f8024000 {
	compatible = "atmel,at91sam9x5-i2c";
	reg = <0xf8024000 0x4000>;
	interrupts = <34 4 6>;
	dmas = <&dma0 0x00000001 0x06000000>,
	       <&dma0 0x00000001 0x07000000>;
	dma-names = "tx", "rx";
};
