* Cadence SD/SDIO/eMMC Host Controller

Required properties:
- compatible: should be "cdns,sd4hc".
- reg: offset and length of the register set for the device.
- interrupts: a single interrupt specifier.
- clocks: phandle to the input clock.

Optional properties:
For eMMC configuration, supported speed modes are not indicated by the SDHCI
Capabilities Register.  Instead, the following properties should be specified
if supported.  See mmc.txt for details.
- mmc-ddr-1_8v
- mmc-ddr-1_2v
- mmc-hs200-1_8v
- mmc-hs200-1_2v
- mmc-hs400-1_8v
- mmc-hs400-1_2v

Example:
	emmc: sdhci@5a000000 {
		compatible = "cdns,sd4hc";
		reg = <0x5a000000 0x400>;
		interrupts = <0 78 4>;
		clocks = <&clk 4>;
		bus-width = <8>;
		mmc-ddr-1_8v;
		mmc-hs200-1_8v;
		mmc-hs400-1_8v;
	};
