NXP PCF2123 SPI Real Time Clock

Required properties:
- compatible: should be: "nxp,rtc-pcf2123"
                      or "microcrystal,rv2123"
- reg: should be the SPI slave chipselect address

Optional properties:
- spi-cs-high: PCF2123 needs chipselect high

Example:

pcf2123: rtc@3 {
	compatible = "nxp,rtc-pcf2123"
	reg = <3>
	spi-cs-high;
};