I2C for SiRFprimaII platforms

Required properties :
- compatible : Must be "sirf,prima2-i2c"
- reg: physical base address of the controller and length of memory mapped
     region.
- interrupts: interrupt number to the cpu.

Optional properties:
- clock-frequency : Constains desired I2C/HS-I2C bus clock frequency in Hz.
  The absence of the property indicates the default frequency 100 kHz.

Examples :

i2c0: i2c@b00e0000 {
    compatible = "sirf,prima2-i2c";
    reg = <0xb00e0000 0x10000>;
    interrupts = <24>;
};
