ISL12026 I2C RTC/EEPROM

ISL12026 is an I2C RTC/EEPROM combination device.  The RTC and control
registers respond at bus address 0x6f, and the EEPROM array responds
at bus address 0x57.  The canonical "reg" value will be for the RTC portion.

Required properties supported by the device:

 - "compatible": must be "isil,isl12026"
 - "reg": I2C bus address of the device (always 0x6f)

Optional properties:

 - "isil,pwr-bsw": If present PWR.BSW bit must be set to the specified
                   value for proper operation.

 - "isil,pwr-sbib": If present PWR.SBIB bit must be set to the specified
                    value for proper operation.


Example:

	rtc@6f {
		compatible = "isil,isl12026";
		reg = <0x6f>;
		isil,pwr-bsw = <0>;
		isil,pwr-sbib = <1>;
	}