ASoC: simple-card.c: add missing of_node_put()

It is missing of_node_put() for platform.
This patch fixup it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87ilerjcvr.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/generic/simple-card.c

@@ -422,6 +422,7 @@ static int __simple_for_each_link(struct asoc_simple_priv *priv,
 		}
 
 		of_node_put(codec);
+		of_node_put(plat);
 		node = of_get_next_child(top, node);
 	} while (!is_top && node);