overlay: Drop hard-coded battery capacity

There are different generations of battery modules available for the
FP3; the kernel is aware of them. Use that information at runtime rather
than hardcoding some specific value.

FP3 battery capacity is anyway around 3000 mAh, not at 2000 as
configured so far.

Issue: FP3-A13#86
Change-Id: Ia025ddf9621a6012cd8b0a876218183705d0e886
Depends-On: Id93d13fb8de63a2375f2948449a380ebb746a166
1 file changed