dt-bindings: mmc: add bindings for hi3798cv200-dw-mshc

* Hisilicon Hi3798CV200 specific extensions to the Synopsys Designware Mobile

  Storage Host Controller

Read synopsys-dw-mshc.txt for more details

The Synopsys designware mobile storage host controller is used to interface

a SoC with storage medium such as eMMC or SD/MMC cards. This file documents

differences between the core Synopsys dw mshc controller properties described

by synopsys-dw-mshc.txt and the properties used by the Hisilicon Hi3798CV200

specific extensions to the Synopsys Designware Mobile Storage Host Controller.

Required Properties:

- compatible: Should contain "hisilicon,hi3798cv200-dw-mshc".

- clocks: A list of phandle + clock-specifier pairs for the clocks listed

  in clock-names.

- clock-names: Should contain the following:

	"ciu" - The ciu clock described in synopsys-dw-mshc.txt.

	"biu" - The biu clock described in synopsys-dw-mshc.txt.

	"ciu-sample" - Hi3798CV200 extended phase clock for ciu sampling.

	"ciu-drive"  - Hi3798CV200 extended phase clock for ciu driving.

Example:

	emmc: mmc@9830000 {

		compatible = "hisilicon,hi3798cv200-dw-mshc";

		reg = <0x9830000 0x10000>;

		interrupts = <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>;

		clocks = <&crg HISTB_MMC_CIU_CLK>,

			 <&crg HISTB_MMC_BIU_CLK>,

			 <&crg HISTB_MMC_SAMPLE_CLK>,

			 <&crg HISTB_MMC_DRV_CLK>;

		clock-names = "ciu", "biu", "ciu-sample", "ciu-drive";

		fifo-depth = <256>;

		clock-frequency = <200000000>;

		cap-mmc-highspeed;

		mmc-ddr-1_8v;

		mmc-hs200-1_8v;

		non-removable;

		bus-width = <8>;

	};