ASoC: soc-core: set component->debugfs_root NULL

To be more safety code, let's set NULL to component->debugfs_root
when it was cleanuped.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87muglahq0.wl-kuninori.morimoto.gx@renesas.comReviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-core.c

@@ -171,7 +171,10 @@ static void soc_init_component_debugfs(struct snd_soc_component *component)
 
 static void soc_cleanup_component_debugfs(struct snd_soc_component *component)
 {
+	if (!component->debugfs_root)
+		return;
 	debugfs_remove_recursive(component->debugfs_root);
+	component->debugfs_root = NULL;
 }
 
 static int dai_list_show(struct seq_file *m, void *v)