stylus_in_proximity was introduced to support touch arbitration
before in range was supported. With in range event, the logic
changed. stylus_in_proximity should be set for both in prox and
in range events.

To finish a clean touch arbitration logic, we should send touch
up (if it was down) before posting any general pen events.
Signed-off-by: NPing Cheng <pingc@wacom.com>
Reviewed-by: NJason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>