By this commit user gets possibility to register USB
device satutus callback. This callback represents device state
and is added so user could know what happend to USB device.
Callback is registered by providing it to usb_enable()
USB api is extended by this callback handler.
Samples using using USB are by default provide no callback
and the usb_enable() is called with NULL parameter.
Status callback registered by hid class is deleted as now
USB device has global callback for all classes within device.
Signed-off-by: Emil Obalski <emil.obalski@nordicsemi.no>
2128750138