power: supply: Classify Battery Monitor Systems as batteries

CAF's new fuel gauge drivers report POWER_SUPPLY_TYPE_BMS (Battery
Monitor System) instead of POWER_SUPPLY_TYPE_BATTERY (battery), and
rightfully so because it describes their purpose more accurately.

Update the power_supply_is_system_supplied function to recognize BMS
power supplies as batteries to prevent it from attempting to query the
POWER_SUPPLY_PROP_ONLINE property on our fuel gauge drivers.

Signed-off-by: Danny Lin <danny@kdrag0n.dev>
Signed-off-by: danascape <danascape@gmail.com>