[ Upstream commit 20bbb312 ]

This is how userspace checks for touchscreen devices most reliably.
Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>