HID: asus: Add support for multi-touch touchpad on Medion Akoya E1239T

The multi-touch touchpad found on the Medion Akoya E1239T's keyboard-dock,
uses the same custom multi-touch protocol as the Asus keyboard-docks
(same chipset vendor, Integrated Technology Express / ITE).

Add support for this using the existing multi-touch touchpad support in
the hid-asus driver.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>