Init AXP2101 from C code for T-Watch-S3

[bill88t]

This skips the need to do the PMIC init for sane default usage.
Pending testing and consideration of which ldo's to enable on boot.

[bill88t]

Ready to go. Tested by a different board revision and my own unit.
This ensures even on early revisions which lack AXP2101 default settings, everything will work out of the box and removes the need of having to configure pmic.

[bill88t]

IMPORTANT! Some early engineering units have efuses that incorrectly attempt to charge the batteries to 4.35V.
Even on factory fw.

This last commit will forcefully set the charging target to be 4.2V as intended.

[RetiredWizard]

I loaded this artifact and it runs my clock program fine, I didn't test any of the charging components but as far as I can see everything seems to be working as it should. (display, WiFi, speaker, touchscreen)

[bill88t]

I'll get trickle charging in too, one moment.

[bill88t]

Alright this is now ready to go, hopefully no more "discoveries".

Tested it, it now charges @ 500mA until it reaches approx 4.185V.
I'm not very knowledgeable in battery chemistry but I have a feeling I shouldn't permit full 4.2V charge.
Verified with a "Battery Doctor" and the pmic adc reading.

[tannewt]

Thank you!