Hook up RTC for sleeping and timekeeping

[tannewt]

[tannewt]

#4110 Allows us to set the RTC. For sleeping, we need to modify https://github.com/adafruit/circuitpython/blob/main/ports/raspberrypi/supervisor/port.c#L164-L187 for sleep support.

[xorbit]

I don't know enough to know if it's related to this issue, but where time.time() used to fail because no RTC was attached, it now seems to produce seemingly random numbers (but they're from a repeating set) on the RPi Pico.

[tannewt]

@microdev1 any idea if your RTC work should have fixed time.time?

[microdev1]

It seems like common_hal_rtc_init() is not getting called which leads to generation of random numbers.
I am not sure where to add a call for it, how do other ports handle RTC initialization?

[tannewt]

@microdev1 I suspect RTC init is done in port_init in supervisor/port.c.

[microdev1]

port_init works... since this is a small change I might include it with my UART work or maybe you can fit it in somewhere. :)

[tannewt]

Fixed by #4816