HID: logitech-dj: fix return value of logi_dj_recv_query_hidpp_devices

We should return 'retval' as the correct return value
instead of always zero.

Fixes: 74808f91

 ("HID: logitech-dj: add support for non unifying receivers")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>