Lantiq Synchronous Serial Controller (SSC) SPI master driver

Required properties:
- compatible: "lantiq,ase-spi", "lantiq,falcon-spi", "lantiq,xrx100-spi"
- #address-cells: see spi-bus.txt
- #size-cells: see spi-bus.txt
- reg: address and length of the spi master registers
- interrupts: should contain the "spi_rx", "spi_tx" and "spi_err" interrupt.


Optional properties:
- clocks: spi clock phandle
- num-cs: see spi-bus.txt, set to 8 if unset
- base-cs: the number of the first chip select, set to 1 if unset.

Example:


spi: spi@E100800 {
	compatible = "lantiq,xrx200-spi", "lantiq,xrx100-spi";
	reg = <0xE100800 0x100>;
	interrupt-parent = <&icu0>;
	interrupts = <22 23 24>;
	interrupt-names = "spi_rx", "spi_tx", "spi_err";
	#address-cells = <1>;
	#size-cells = <1>;
	num-cs = <6>;
	base-cs = <1>;
};
