da9063_rtc: Add new driver for the Dialog Semiconductor DA9063 RTC

[jrtc27]

Summary

This is a simple RTC present in the PMIC, supporting 1s precision.

This is the PMIC on SiFive's HiFive Unmatched.

MFC after: 1 week

[jrtc27]

Add missing utc_offset call for the local time RTC case

[imp]

No clue of the talking to the hardware part is right, but I believe the time handling is now correct.

[mhorne]

sys/dev/dialog/da9063/da9063_rtc.c

171–173

Isn't ct.min != oldct.min the only check that matters here?

[jrtc27]

sys/dev/dialog/da9063/da9063_rtc.c

171–173

In practice yes, but *technically* you could, say, get preempted for an {hour,day,month,year} (which in reality would only ever happen if using a debugger and you got unlucky) so {min, hour,day,mon,year} would fully wrap around, and it felt wrong to be lazy.

[jrtc27]

Renamed da9063 to da9063_pmic