ds2782_battery: Add power_supply_changed() calls for proper uevent support

This patch affects on Android battery indicator. Battery driver should
send uevent message when battery status changes in order to get Android
battery level dynamically updated. Delayed work was added to periodically
check battery status and capacity.

Signed-off-by: Evgeny Romanov <romanov@neurosoft.ru>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>