HID: multitouch: Add pointstick support for Cirque Touchpad

Cirque Touchpad/Pointstick combo is similar to Alps devices, it requires
MT_CLS_WIN_8_DUAL to expose its pointstick as a mouse.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>