Altera SOCFPGA SDRAM Controller

Required properties:
- compatible : Should contain "altr,sdr-ctl" and "syscon".
  syscon is required by the Altera SOCFPGA SDRAM EDAC.
- reg : Should contain 1 register range (address and length)

Example:
	sdr: sdr@ffc25000 {
		compatible = "altr,sdr-ctl", "syscon";
		reg = <0xffc25000 0x1000>;
	};