Synopsys Designware Mobile Storage Host Controller extensions
used in Synopsys ARC devboards

Required Properties:

* compatible: should be - "snps,dw-mshc".
* bus-width: number of data lines connected to the controller.
* clocks: from common clock binding: handle to biu and ciu clocks for the
  bus interface unit clock and the card interface unit clock.
* clock-names: from common clock binding: Shall be "biu" and "ciu".

Optional properties:

* fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
  specified, the default value of the fifo size is determined from the
  controller registers.
* fifo-mode: Don't use DMA.
* max-frequency: Maximum operating clock frequency, driver uses 'ciu' clock
  frequency if it is not set.

Example:

mmc0@f000a000 {
	compatible = "snps,dw-mshc";
	reg = <0xf000a000 0x400>;

	bus-width = <4>;
	fifo-depth = <256>;
	clocks = <&mmcclk_biu>, <&mmcclk_ciu>;
	clock-names = "biu", "ciu";
	max-frequency = <25000000>;
};

