HID: wacom: add defines for new Cintiq and DTU outbound tracking

There are screen to tablet offsets for newer Cintiq and DTU models.
These offsets serve as outbound tracking for those display tablets.

Use defines instead of hardcoded numbers for the offsets.

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