[ Upstream commit 20bbb312079494a406c10c90932e3c80837c9d94 ]

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