chardev/wctable: don't free the instance in wctablet_chr_finalize

Object is supposed to be freed by invoking obj->free, and not
obj->instance_finalize. This would lead to use-after-free followed by
double free in object_unref/object_finalize.

Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20211117142349.836279-1-d-tatianin@yandex-team.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

chardev/wctablet.c

@@ -320,7 +320,6 @@ static void wctablet_chr_finalize(Object *obj)
     TabletChardev *tablet = WCTABLET_CHARDEV(obj);
 
     qemu_input_handler_unregister(tablet->hs);
-    g_free(tablet);
 }
 
 static void wctablet_chr_open(Chardev *chr,