HID: wacom: Correct distance scale for 2nd-gen Intuos devices

Distance values reported by 2nd-gen Intuos tablets are on an inverted
scale (0 == far, 63 == near). We need to change them over to a normal
scale before reporting to userspace or else userspace drivers and
applications can get confused.

Ref: https://github.com/linuxwacom/input-wacom/issues/98


Fixes: eda01dab ("HID: wacom: Add four new Intuos devices")
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Jiri Kosina <jkosina@suse.cz>