osdep/macosx: add default switch cases to suppress Wswitch

osdep/macosx_events.m

@@ -292,6 +292,8 @@ void cocoa_set_mpv_handle(struct mpv_handle *ctx)
         _ctx = nil;
         break;
     }
+    default:
+        break;
     }
 }
 

osdep/macosx_touchbar.m

@@ -307,6 +307,8 @@
         [self handlePropertyChange:(mpv_event_property *)event->data];
         break;
     }
+    default:
+        break;
     }
 }