dt-bindings: mmc: sdhci-msm: Add interconnect BW scaling strings

- qcom,dll-config: Chipset and Platform specific value. Use this field to

	specify the DLL_CONFIG register value as per Hardware Programming Guide.

Optional Properties:

* Following bus parameters are required for interconnect bandwidth scaling:

- interconnects: Pairs of phandles and interconnect provider specifier

		 to denote the edge source and destination ports of

		 the interconnect path.

- interconnect-names: For sdhc, we have two main paths.

		1. Data path : sdhc to ddr

		2. Config path : cpu to sdhc

		For Data interconnect path the name supposed to be

		is "sdhc-ddr" and for config interconnect path it is

		"cpu-sdhc".

		Please refer to Documentation/devicetree/bindings/

		interconnect/ for more details.

Example:

	sdhc_1: sdhci@f9824900 {

		clocks = <&gcc GCC_SDCC1_APPS_CLK>, <&gcc GCC_SDCC1_AHB_CLK>;

		clock-names = "core", "iface";

		interconnects = <&qnoc MASTER_SDCC_ID &qnoc SLAVE_DDR_ID>,

				<&qnoc MASTER_CPU_ID &qnoc SLAVE_SDCC_ID>;

		interconnect-names = "sdhc-ddr","cpu-sdhc";

		qcom,dll-config = <0x000f642c>;

		qcom,ddr-config = <0x80040868>;