ACPI battery: don't invoke power_supply_changed twice when battery is hot-added

When battery is hot-added, we should not invoke power_supply_changed
in acpi_battery_notify, because it has been invoked in acpi_battery_update,
and battery->bat.changed_work is queued in keventd already.
https://bugzilla.kernel.org/show_bug.cgi?id=16244

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Alexey Starikovskiy <astarikovskiy@sude.de>
Signed-off-by: Len Brown <len.brown@intel.com>