Input: xpad - add constants for GIP interface numbers

[ Upstream commit f9b2e603c6216824e34dc9a67205d98ccc9a41ca ]

Wired GIP devices present multiple interfaces with the same USB identification
other than the interface number. This adds constants for differentiating two of
them and uses them where appropriate

Signed-off-by: Vicki Pfau <vi@endrift.com>
Link: https://lore.kernel.org/r/20230411031650.960322-2-vi@endrift.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>