Subdivision: remove info message that GPU subdivision being used

This is the normal case, it's only when both CPU and GPU subdivision is used
that the user needs to be informed that performance is suboptimal.

source/blender/modifiers/intern/MOD_subsurf.cc

@@ -437,9 +437,6 @@ static void panel_draw(const bContext *C, Panel *panel)
           if (runtime_data->used_cpu) {
             uiItemL(layout, "Using both CPU and GPU subdivision", ICON_INFO);
           }
-          else {
-            uiItemL(layout, "Using GPU subdivision", ICON_INFO);
-          }
         }
       }
     }