ASoC: simple-card: tidyup prefix for snd_soc_codec_conf

Current simple-card is handling "prefix" by many ways.
But, it is not useful and readable.
We want to do is that allow having it everywere.
This patch supports it.
It will be overwrote if lower node has it.

sound {
	simple-audio-card,prefix = "xxx"; // initial

	simple-audio-card,dai-link {
		prefix = "xxx"; // overwrite
		cpu {
			...
		};
		codec {
			prefix = "xxx"; // overwrite
		};
	};
};
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/generic/simple-card.c

@@ -177,8 +177,9 @@ static int asoc_simple_card_dai_link_of_dpcm(struct device_node *top,
 	struct device *dev = simple_priv_to_dev(priv);
 	struct snd_soc_dai_link *dai_link = simple_priv_to_link(priv, link_idx);
 	struct simple_dai_props *dai_props = simple_priv_to_props(priv, link_idx);
-	struct snd_soc_card *card = simple_priv_to_card(priv);
 	struct asoc_simple_dai *dai;
+	struct snd_soc_dai_link_component *codecs = dai_link->codecs;
+
 	char prop[128];
 	char *prefix = "";
 	int ret;
@@ -189,10 +190,8 @@ static int asoc_simple_card_dai_link_of_dpcm(struct device_node *top,
 
 	if (is_fe) {
 		int is_single_links = 0;
-		struct snd_soc_dai_link_component *codecs;
 
 		/* BE is dummy */
-		codecs			= dai_link->codecs;
 		codecs->of_node		= NULL;
 		codecs->dai_name	= "snd-soc-dummy-dai";
 		codecs->name		= "snd-soc-dummy";
@@ -248,19 +247,17 @@ static int asoc_simple_card_dai_link_of_dpcm(struct device_node *top,
 
 		ret = asoc_simple_card_set_dailink_name(dev, dai_link,
 							"be.%s",
-							dai_link->codecs->dai_name);
+							codecs->dai_name);
 		if (ret < 0)
 			return ret;
 
 		/* check "prefix" from top node */
-		snd_soc_of_parse_audio_prefix(card, cconf,
-					      dai_link->codecs->of_node,
+		snd_soc_of_parse_node_prefix(top, cconf, codecs->of_node,
 					      PREFIX "prefix");
-		/* check "prefix" from each node if top doesn't have */
-		if (!cconf->of_node)
-			snd_soc_of_parse_node_prefix(np, cconf,
-						     dai_link->codecs->of_node,
-						     "prefix");
+		snd_soc_of_parse_node_prefix(node, cconf, codecs->of_node,
+					     "prefix");
+		snd_soc_of_parse_node_prefix(np, cconf, codecs->of_node,
+					     "prefix");
 	}
 
 	asoc_simple_card_parse_convert(dev, top,  PREFIX, &dai_props->adata);