zoom: Rename zoom_area_center_from_pointer to zoom_area_center_from_point

It doesn't do anything with a pointer, and zoom can be initiated by the
keyboard, so the name was a little confusing.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

src/zoom.c

@@ -69,7 +69,7 @@ weston_zoom_pick_seat(struct weston_compositor *compositor)
 }
 
 static void
-zoom_area_center_from_pointer(struct weston_output *output,
+zoom_area_center_from_point(struct weston_output *output,
 			    wl_fixed_t *x, wl_fixed_t *y)
 {
 	float level = output->zoom.spring_z.current;
@@ -96,7 +96,7 @@ weston_output_update_zoom_transform(struct weston_output *output)
 	    level == 0.0f)
 		return;
 
-	zoom_area_center_from_pointer(output, &x, &y);
+	zoom_area_center_from_point(output, &x, &y);
 
 	global_x = wl_fixed_to_double(x);
 	global_y = wl_fixed_to_double(y);