HID: logitech-dj: add support for Logitech Bluetooth Mini-Receiver

Add support for the Logitech Bluetooth Mini-Receiver in HID proxy mode

This requires some special handing in dj_find_receiver_dev because the
BT Mini-Receiver contains a built-in hub and has separate USB-devices
for the keyboard and mouse interfaces, rather then using 2 interfaces on
a single USB device. Otherwise this receiver works identical to the
standard non-unifying nano receivers.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>