ACPI / battery: call ACPI notifier chain in acpi_battery_notify

Allow other drivers to subscribe to battery status notifications.
Just like AC driver does.

Signed-off-by: Alexander Mezin <mezin.alexander@gmail.com>
Acked-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>