HID: wacom: Use tablet-provided touch height/width values for INTUOSHT

The current generation of "Intuos" tablets (i.e. INTUOSHT) report touch
width and height data just like the "Intuos Pro" do. This commit changes
the code to allow these tablets to use the appropriate codepath instead
of the one intended for Intuos5/Bamboo.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>