Animate transitions for zoom focus point change.

Handle the transition when focus changes from text cursor to
mouse pointer or vice versa.
diff --git a/src/shell.c b/src/shell.c
index bc2a987..9186bdb 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -2185,10 +2185,7 @@
 
 			output->zoom.spring_z.target = output->zoom.level;
 
-			weston_output_update_zoom(output,
-			                          seat->pointer->x,
-						  seat->pointer->y,
-						  ZOOM_FOCUS_POINTER);
+			weston_output_update_zoom(output, output->zoom.type);
 		}
 	}
 }