power: bq27xxx_battery: Reorganize I2C into a module

Separate out I2C functionality into a module. This fixes several small
issues and simplifies the driver initialization.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/Makefile

@@ -31,6 +31,7 @@ obj-$(CONFIG_BATTERY_IPAQ_MICRO) += ipaq_micro_battery.o
 obj-$(CONFIG_BATTERY_WM97XX)	+= wm97xx_battery.o
 obj-$(CONFIG_BATTERY_SBS)	+= sbs-battery.o
 obj-$(CONFIG_BATTERY_BQ27XXX)	+= bq27xxx_battery.o
+obj-$(CONFIG_BATTERY_BQ27XXX_I2C) += bq27xxx_battery_i2c.o
 obj-$(CONFIG_BATTERY_DA9030)	+= da9030_battery.o
 obj-$(CONFIG_BATTERY_DA9052)	+= da9052-battery.o
 obj-$(CONFIG_CHARGER_DA9150)	+= da9150-charger.o