* AHCI SATA Controller

SATA nodes are defined to describe on-chip Serial ATA controllers.
Each SATA controller should have its own node.

Required properties:
- compatible        : compatible list, one of "snps,spear-ahci",
                      "snps,exynos5440-ahci", "ibm,476gtr-ahci",
                      "allwinner,sun4i-a10-ahci", "fsl,imx53-ahci"
                      "fsl,imx6q-ahci" or "snps,dwc-ahci"
- interrupts        : <interrupt mapping for SATA IRQ>
- reg               : <registers mapping>

Optional properties:
- dma-coherent      : Present if dma operations are coherent
- clocks            : a list of phandle + clock specifier pairs
- target-supply     : regulator for SATA target power

"fsl,imx53-ahci", "fsl,imx6q-ahci" required properties:
- clocks            : must contain the sata, sata_ref and ahb clocks
- clock-names       : must contain "ahb" for the ahb clock

Examples:
        sata@ffe08000 {
		compatible = "snps,spear-ahci";
		reg = <0xffe08000 0x1000>;
		interrupts = <115>;
        };

	ahci: sata@01c18000 {
		compatible = "allwinner,sun4i-a10-ahci";
		reg = <0x01c18000 0x1000>;
		interrupts = <56>;
		clocks = <&pll6 0>, <&ahb_gates 25>;
		target-supply = <&reg_ahci_5v>;
	};