power: bq27xxx: fix reading for bq27000 and bq27010

power: bq27xxx: fix reading for bq27000 and bq27010

bug: the driver reports funny capacity values:

root@letux:/sys/class/power_supply/bq27000-battery# cat uevent
POWER_SUPPLY_NAME=bq27000-battery
POWER_SUPPLY_STATUS=Charging
POWER_SUPPLY_PRESENT=1
POWER_SUPPLY_VOLTAGE_NOW=3702000
POWER_SUPPLY_CURRENT_NOW=-464635
POWER_SUPPLY_CAPACITY=1536			<- over 100% is magic
POWER_SUPPLY_CAPACITY_LEVEL=Normal
POWER_SUPPLY_TEMP=311
POWER_SUPPLY_TIME_TO_FULL_NOW=10440
POWER_SUPPLY_TECHNOLOGY=Li-ion
POWER_SUPPLY_CHARGE_FULL=805450
POWER_SUPPLY_CHARGE_NOW=1068
POWER_SUPPLY_CHARGE_FULL_DESIGN=8844998	<- battery has just 1200 mAh
POWER_SUPPLY_CYCLE_COUNT=21
POWER_SUPPLY_ENERGY_NOW=0
POWER_SUPPLY_POWER_AVG=0
POWER_SUPPLY_HEALTH=Good
POWER_SUPPLY_MANUFACTURER=Texas Instruments

reason: the state of charge and the design capacity register are single
byte only. The design capacity returns the higer order byte.

tested: GTA04 with Openmoko/FIC HF08x battery (using hdq)

Fixes: d74534c27775 ("power: bq27xxx_battery: Add support for additional bq27xxx family devices")
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Acked-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>