power: supply: bq27xxx_battery: Notify also about status changes

User-space might be interested in receiving uevents when the charging
starts/stops or if conditions of battery changes (e.g.
over-temperature).  Notify about changes in battery also when the flags
change, not only SoC.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>