Some panels advertise both pointer/touch capabilities but without having
real capability of driving a cursor (they're basically touch panels) and
use USB as a communication tunnel to transfer/send out input events.
As we can't really tell if they're fake or not, only advertise to
clients pointer capabilities if we detect movement on the cursor/pointer.
We handle it at lower level as that allows to handle the case where
removal of a real pointer should also remove the cursor from being
displayed on the screen.
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>