vaapisink: fix GstNavigation "mouse-move" event.
vaapisink: fix GstNavigation "mouse-move" event.

Really use the motion event coordinates to propagate the "mouse-move"
event to upper layer, instead of those from a button event. Those are
technically the same though.

ceyusa/gstreamer-vaapi,GStreamer/gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,GStreamer/gstreamer-vaapi,ceyusa/gstreamer-vaapi,CapOM/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi