HID: logitech-dj: allow devices to request full pairing information

Register 0xB5 should be handled specially no matter what function is
used. This allows to retrieve the serial and the Quad ID from
hid-logitech-hidpp directly.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>