Add support for TI BQ78Z100, I2C interface gas gauge.
It provides a fully integrated safety protection
and authentication for 1 to 2-series cell Li-Ion and
Li-Polymer battery packs.

The patch was tested with BQ78Z100 equipment.

CASE I:  Discharging:
	POWER_SUPPLY_NAME=bq78z100-0
	POWER_SUPPLY_STATUS=Discharging
	POWER_SUPPLY_PRESENT=1
	POWER_SUPPLY_VOLTAGE_NOW=3386000
	POWER_SUPPLY_CURRENT_NOW=-5000
	POWER_SUPPLY_CAPACITY=27
	POWER_SUPPLY_CAPACITY_LEVEL=Normal
	POWER_SUPPLY_TEMP=269
	POWER_SUPPLY_TIME_TO_EMPTY_NOW=1249920
	POWER_SUPPLY_TECHNOLOGY=Li-ion
	POWER_SUPPLY_CHARGE_FULL=6494000
	POWER_SUPPLY_CHARGE_NOW=1736000
	POWER_SUPPLY_CHARGE_FULL_DESIGN=6000000
	POWER_SUPPLY_CYCLE_COUNT=1
	POWER_SUPPLY_POWER_AVG=-20000
	POWER_SUPPLY_HEALTH=Good
	POWER_SUPPLY_MANUFACTURER=Texas Instruments

CASE II : No discharging current:
	POWER_SUPPLY_NAME=bq78z100-0
	POWER_SUPPLY_STATUS=Not charging
	POWER_SUPPLY_PRESENT=1
	POWER_SUPPLY_VOLTAGE_NOW=3386000
	POWER_SUPPLY_CURRENT_NOW=0
	POWER_SUPPLY_CAPACITY=27
	POWER_SUPPLY_CAPACITY_LEVEL=Normal
	POWER_SUPPLY_TEMP=270
	POWER_SUPPLY_TECHNOLOGY=Li-ion
	POWER_SUPPLY_CHARGE_FULL=6494000
	POWER_SUPPLY_CHARGE_NOW=1734000
	POWER_SUPPLY_CHARGE_FULL_DESIGN=6000000
	POWER_SUPPLY_CYCLE_COUNT=1
	POWER_SUPPLY_POWER_AVG=0
	POWER_SUPPLY_HEALTH=Good
	POWER_SUPPLY_MANUFACTURER=Texas Instruments
Signed-off-by: LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>