usbtracker: * track dedicated charger, not only cable             * only send signals when the connection status changes
usbtracker: * track dedicated charger, not only cable
            * only send signals when the connection status changes

Signed-off-by: Philippe De Swert <24f3ca4ad20fb8d7f8698e5ac6e2304d48abcaf5@jollamobile.com>

spiiroin/dsme,philippedeswert/dsme,philippedeswert/dsme,philippedeswert/dsme,spiiroin/dsme