Amlogic Meson SPI controller

* slave SPICC

Required properties:
 - compatible: should be "amlogic,slave-spicc"
 - reg: physical base address and length of the controller registers
 - interrupts: The interrupt specifier
 - clock-names: Must contain "core", "comp"
 - clocks: phandle of the input clock for the baud rate generator
 - pinctrl-names: Should contain only one value - "default"
 - cs-num: Should be 0~3
 - spi-mode: Refer to spi-summary.txt
 - vmem-bus-num: Should be 0~16

Optional properties:

Examples:
	sspicc1: sspi@15000 {
		compatible = "amlogic,slave-spicc";
		reg = <0x15000 0x44>;
		interrupts = <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&clkc CLKID_SPICC1>,
			 <&clkc CLKID_SPICC1_COMP>;
		clock-names = "core", "comp";
		pinctrl-names = "default";
		pinctrl-0 = <&spicc1_pins_dv &spicc1_pins_cs_dv>;
		cs-num = <0>;
		spi-mode = <0x0>;
		vmem-bus-num = <0>;
	};
