Freescale Multi Mode DDR controller (MMDC)

Required properties :
- compatible : should be one of following:
	for i.MX6Q/i.MX6DL:
	- "fsl,imx6q-mmdc";
	for i.MX6QP:
	- "fsl,imx6qp-mmdc", "fsl,imx6q-mmdc";
	for i.MX6SL:
	- "fsl,imx6sl-mmdc", "fsl,imx6q-mmdc";
	for i.MX6SLL:
	- "fsl,imx6sll-mmdc", "fsl,imx6q-mmdc";
	for i.MX6SX:
	- "fsl,imx6sx-mmdc", "fsl,imx6q-mmdc";
	for i.MX6UL/i.MX6ULL/i.MX6ULZ:
	- "fsl,imx6ul-mmdc", "fsl,imx6q-mmdc";
	for i.MX7ULP:
	- "fsl,imx7ulp-mmdc", "fsl,imx6q-mmdc";
- reg : address and size of MMDC DDR controller registers

Optional properties :
- clocks : the clock provided by the SoC to access the MMDC registers

Example :
	mmdc0: memory-controller@21b0000 { /* MMDC0 */
		compatible = "fsl,imx6q-mmdc";
		reg = <0x021b0000 0x4000>;
		clocks = <&clks IMX6QDL_CLK_MMDC_P0_IPG>;
	};

	mmdc1: memory-controller@21b4000 { /* MMDC1 */
		compatible = "fsl,imx6q-mmdc";
		reg = <0x021b4000 0x4000>;
		status = "disabled";
	};