HID: multitouch: Enable multi-input for Synaptics pointstick/touchpad device

HID: multitouch: Enable multi-input for Synaptics pointstick/touchpad device

BugLink: https://bugs.launchpad.net/bugs/1908992
Pointstick and its left/right buttons on HP EliteBook 850 G7 need
multi-input quirk to work correctly.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
(cherry picked from commit c3d6eb6e54373f297313b65c1f2319d36914d579)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: William Breathitt Gray <william.gray@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>