HID: multitouch: Lenovo X1 Tablet Gen3 trackpoint and buttons

[ Upstream commit 8d5037dca7c2089f27e5903c2aecfc5bb10d7806 ]

Add support for the trackpoint and three mouse buttons on the type cover
of the Lenovo X1 Tablet Gen3.

This is the same as with the 2nd generation Lenovo X1 Tablet.

Signed-off-by: Mikael Wikström <leakim.wikstrom@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>