bq25890: Export the battery temperature
The bq25895 charger is monitoring the battery temperature using the battery's thermistor to turn off charging when the temperature gets high. It would be handy to be able to monitor this temperature with thermal zones - the closest thing,
max170xx_battery, provides the information from the on-die sensor, which
should be close, but not identical to what bq25895 sees (since Dogwood, the gauge gets quickly affected by SoC heat, while the battery itself does not, so it's not so close anymore).
sudo i2cget -f -y 3 0x6a 0x10can be used to get the battery temperature