Freescale Asynchronous Samplerate Converter (ASRC) core device

Required properties:
- compatible : "fsl,imx6-asrc-core" for the ASRC used on i.MX6
- reg : Should contain ASRC registers location and length
- fsl,asrc-dma-events : Should contain the DMA request lines for the input and
output fifos of every ASRC pair
- interrupts : Should contain the interrupt address locations and length
- clocks : Should contain the clocktree reference and clocktree id
- clock-names : Should contain the name of the ASRC clock in the clocktree

Optional properties:
- status : "okay" enables the ASRC core
- channels : Should contain the number of channels for all ASRC pairs in use.
The sum of all channels should not exceed the max channels available for the
ASRC. If omitted, the default channel mapping is <2 2 6>
- clock-table-muxid : Should contain an integer array of ASRC clock muxids to
 be used with the ASRC
- clock-table-name : Should contain a string list of ascii clocknames to be used
with the ASRC
- clock-table-rate : Should contain an integer array of the initial ideal clock
sample rates (in Hertz) of all the clocknames to be used with the ASRC.

Note: clock-table-muxid, clock-table-name, clock-table-rate should contain the
same number of entries. Regardless of whether the options are specified, the
ASRC "NONE" and "ASRCK1" clocks will always be in the table for use.

Example:

asrc: asrc@02034000 {
	status = "okay";
	compatible = "fsl,imx6-asrc-core";
	fsl,asrc-dma-events = <20 17 21 18 22 19>;
	channels = <2 2 6>; /* A B C */
	reg = <0x02034000 0x4000>;
	interrupts = <0 50 0x04>;
	clocks = <&clks 107>;
	clock-names = "asrc";
	clock-table-muxid = <6 8>;
	clock-table-name = "CLK_EXT", "CLK_ESAI_TX";
	clock-table-rate = <0 12000000>;
};
