HID: wacom: Add outbounding area for DTU1141

DTU1141 has an extra 1 mm tablet active outbounding area on each
side of the display, same as those recently released DTUs.

Signed-off-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>