I2C for Atmel platforms

Required properties :
- compatible : Must be "atmel,at91rm9200-i2c", "atmel,at91sam9261-i2c",
     "atmel,at91sam9260-i2c", "atmel,at91sam9g20-i2c", "atmel,at91sam9g10-i2c"
     or "atmel,at91sam9x5-i2c"
- reg: physical base address of the controller and length of memory mapped
     region.
- interrupts: interrupt number to the cpu.
- #address-cells = <1>;
- #size-cells = <0>;
- clocks: phandles to input clocks.

Optional properties:
- clock-frequency: Desired I2C bus frequency in Hz, otherwise defaults to 100000
- Child nodes conforming to i2c bus binding

Examples :

i2c0: i2c@fff84000 {
	compatible = "atmel,at91sam9g20-i2c";
	reg = <0xfff84000 0x100>;
	interrupts = <12 4 6>;
	#address-cells = <1>;
	#size-cells = <0>;
	clocks = <&twi0_clk>;
	clock-frequency = <400000>;

	24c512@50 {
		compatible = "24c512";
		reg = <0x50>;
		pagesize = <128>;
	}
}
