Revert "backends/x11: Do not reload keymap on new keyboard notifications"

This reverts commit b01edc22f3cf816ec2bbc4e777fb44525a8456a8.

It breaks keybindings on certain physical keyboard layouts.

Closes: https://gitlab.gnome.org/GNOME/mutter/issues/822

src/backends/x11/meta-backend-x11.c

@@ -356,6 +356,7 @@ handle_host_xevent (MetaBackend *backend,
         {
           switch (xkb_ev->any.xkb_type)
             {
+            case XkbNewKeyboardNotify:
             case XkbMapNotify:
               keymap_changed (backend);
               break;