power: supply: bq27xxx: Move temperature reading out of update loop

Most of the functions that read values return a status and put the value
itself in an a function parameter. Update temperature reading to match.

As temp is not checked for changes as part of the update loop, remove
the read of the temperature from the periodic update loop. This saves
I2C/1W bandwidth. It also means we do not have to cache it, fresh
values are read when requested.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240325203129.150030-1-afd@ti.com


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>