Devkit battery charging

Epic: https://source.puri.sm/Librem5/use-cases/issues/89, https://source.puri.sm/Librem5/use-cases/issues/108

bq25890 shows "Not Charging" even when online and the battery voltage is low.

root@pureos:~# cat /sys/class/power_supply/bq25890-charger/online 
1
root@pureos:~# cat /sys/class/power_supply/bq25890-charger/status                                                  
Not charging
root@pureos:~# cat /sys/class/power_supply/bq25890-charger/voltage_now                                                  
3764000