Input: ALPS - handle touchpoints buttons correctly

When pressing any button belonging to the touchpoint, the generated
click events don't belong to the touchpoint but to the touchpad.
This patch fixes this behaviour, the events will be sent via the
correct device, so scrolling with touchpoint is possible.

Signed-off-by: Ulrich Dangel <uli@spamt.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>