Handle the PCF2127 RTC chip the same as PCF2129 when init'ing the chip.

This affects the detection of 24-hour vs AM/PM mode... the ampm bit is in a
different location on 2127 and 2129 chips compared to other nxp rtc chips.
I noticed the 2127 case wasn't being handled correctly when I accidentally
misconfiged my system by claiming my PCF2129 was a 2127.