Qualcomm Snapdragon SDHCI controller

Required properties:
- compatible : "qcom,sdhci-msm-v4"
- reg: Base address and length of registers:
	- Host controller registers (SDHCI)
	- SD Core registers
- clock: interface clock (must accept SD bus clock as a frequency)

Optional properties:
- index: If there is more than one controller - controller index (required
	by generic SDHCI code).
- bus_width: Width of SD/eMMC bus (default 4)
- clock-frequency: Frequency of SD/eMMC bus (default 400 kHz)

Example:

sdhci@07864000 {
	compatible = "qcom,sdhci-msm-v4";
	reg = <0x7864900 0x11c 0x7864000 0x800>;
	index = <0x1>;
	bus-width = <0x4>;
	clock = <&clkc 1>;
	clock-frequency = <200000000>;
};