dt-bindings: milbeaut-m10v-hdmac: Add Socionext Milbeaut HDMAC bindings

* Milbeaut AHB DMA Controller

Milbeaut AHB DMA controller has transfer capability below.

 - device to memory transfer

 - memory to device transfer

Required property:

- compatible:       Should be  "socionext,milbeaut-m10v-hdmac"

- reg:              Should contain DMA registers location and length.

- interrupts:       Should contain all of the per-channel DMA interrupts.

                     Number of channels is configurable - 2, 4 or 8, so

                     the number of interrupts specified should be {2,4,8}.

- #dma-cells:       Should be 1. Specify the ID of the slave.

- clocks:           Phandle to the clock used by the HDMAC module.

Example:

	hdmac1: dma-controller@1e110000 {

		compatible = "socionext,milbeaut-m10v-hdmac";

		reg = <0x1e110000 0x10000>;

		interrupts = <0 132 4>,

			     <0 133 4>,

			     <0 134 4>,

			     <0 135 4>,

			     <0 136 4>,

			     <0 137 4>,

			     <0 138 4>,

			     <0 139 4>;

		#dma-cells = <1>;

		clocks = <&dummy_clk>;

	};