fuel_gauge: Add battery cutoff support

Many fuel gauge ICs offer a battery cutoff/shipping mode functionality that
cutoff charge from the battery. This is often useful for preserving battery
charge on devices while in storage.

Add battery cutoff support to the fuel gauge API with a generic default SBS
driver showing an example of support in tests.

Signed-off-by: Aaron Massey <aaronmassey@google.com>
15 files changed