* I2C

Required properties :

 - device_type : Should be "i2c"
 - reg : Offset and length of the register set for the device

Recommended properties :

 - compatible : compatibility list with 2 entries, the first should
   be "fsl,CHIP-i2c" where CHIP is the name of a compatible processor,
   e.g. mpc8313, mpc8543, mpc8544, mpc5200 or mpc5200b. The second one
   should be "fsl-i2c".
 - interrupts : <a b> where a is the interrupt number and b is a
   field that represents an encoding of the sense and level
   information for the interrupt.  This should be encoded based on
   the information in section 2) depending on the type of interrupt
   controller you have.
 - interrupt-parent : the phandle for the interrupt controller that
   services interrupts for this device.
 - fsl,preserve-clocking : boolean; if defined, the clock settings
   from the bootloader are preserved (not touched).
 - clock-frequency : desired I2C bus clock frequency in Hz.

Examples :

	i2c@3d00 {
		#address-cells = <1>;
		#size-cells = <0>;
		compatible = "fsl,mpc5200b-i2c","fsl,mpc5200-i2c","fsl-i2c";
		cell-index = <0>;
		reg = <0x3d00 0x40>;
		interrupts = <2 15 0>;
		interrupt-parent = <&mpc5200_pic>;
		fsl,preserve-clocking;
	};

	i2c@3100 {
		#address-cells = <1>;
		#size-cells = <0>;
		cell-index = <1>;
		compatible = "fsl,mpc8544-i2c", "fsl-i2c";
		reg = <0x3100 0x100>;
		interrupts = <43 2>;
		interrupt-parent = <&mpic>;
		clock-frequency = <400000>;
	};