dj/HID++ receivers are really a single logical entity, but for BIOS/Windows
compatibility they have multiple USB interfaces. For the upcoming
non-unifying receiver support, we need to listen for events from / bind to
all USB-interfaces of the receiver.

This commit add support to the logitech-dj code for creating a single
dj_receiver_dev struct for all interfaces belonging to a single
USB-device / receiver, in preparation for adding non-unifying receiver
support.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>