input: Transform to surface coordinates outside resource for loop

When we send the pointer motion event, the transform from compositor to
surface coordinates doesn't depend on the resource.  Transform the
coordinates up front instead of everytime we send to a resource.

src/input.c

@@ -172,11 +172,11 @@ default_grab_pointer_motion(struct weston_pointer_grab *grab, uint32_t time,
 
 	weston_pointer_move(pointer, x, y);
 
+	if (pointer->focus)
+		weston_view_from_global_fixed(pointer->focus,
+					      pointer->x, pointer->y, &sx, &sy);
 	resource_list = &pointer->focus_resource_list;
 	wl_resource_for_each(resource, resource_list) {
-		weston_view_from_global_fixed(pointer->focus,
-					      pointer->x, pointer->y,
-					      &sx, &sy);
 		wl_pointer_send_motion(resource, time, sx, sy);
 	}
 }