Ralink SoC RT2880 SPI master controller.

This SPI controller is found on most wireless SoCs made by ralink.

Required properties:
- compatible : "ralink,rt2880-spi"
- reg : The register base for the controller.
- #address-cells : <1>, as required by generic SPI binding.
- #size-cells : <0>, also as required by generic SPI binding.

Child nodes as per the generic SPI binding.

Example:

	spi@b00 {
		compatible = "ralink,rt2880-spi";
		reg = <0xb00 0x100>;

		#address-cells = <1>;
		#size-cells = <0>;

		m25p80@0 {
			compatible = "m25p80";
			reg = <0>;
			spi-max-frequency = <10000000>;
		};
	};