Amlogic Meson I2C controller

Required properties:
 - compatible: must be "amlogic,meson6-i2c" or "amlogic,meson-gxbb-i2c"
 - reg: physical address and length of the device registers
 - interrupts: a single interrupt specifier
 - clocks: clock for the device
 - #address-cells: should be <1>
 - #size-cells: should be <0>

Optional properties:
- clock-frequency: the desired I2C bus clock frequency in Hz; in
  absence of this property the default value is used (100 kHz).

Examples:

	i2c@c8100500 {
		compatible = "amlogic,meson6-i2c";
		reg = <0xc8100500 0x20>;
		interrupts = <0 92 1>;
		clocks = <&clk81>;
		#address-cells = <1>;
		#size-cells = <0>;
	};