x11: always wait for mapped when using --wid

Might help with embedding with mozplugger. I can't confirm whether it
fixes the issue.

See #1090.

video/out/x11_common.c

@@ -944,10 +944,11 @@ int vo_x11_check_events(struct vo *vo)
             break;
         case PropertyNotify:
             if (Event.xproperty.atom == x11->atom_frame_exts) {
-                if (!x11->pseudo_mapped)
+                if (!x11->pseudo_mapped && vo->opts->WinID < 0) {
                     MP_VERBOSE(x11, "not waiting for MapNotify\n");
                     x11->pseudo_mapped = true;
                 }
+            }
             break;
         default:
             if (Event.type == x11->ShmCompletionEvent) {