ASoC: simple-card-utils: check "reg" property on asoc_simple_card_get_dai_id()

We will get DAI ID from "reg" property if it has on DT, otherwise get
it by counting port/endpoint.

But in below case, we need to get DAI ID = 0 via port reg = <0>, but
current implementation returns ID = 1, because it can't judge ID = 0 was
from "non reg" or "reg = <0>".
Thus, it will count port/endpoint number as "non reg" case.

of_graph_parse_endpoint() implementation itself is not a problem,
but because asoc_simple_card_get_dai_id() need to count port/endpoint
number when "non reg" case, it need to know ID = 0 was from
"non reg" or "reg = <0>".
This patch fix this issue.

	port {
		reg = <0>;
		xxxx: endpoint@0 {
		};
=>		xxxx: endpoint@1 {
		};
	};
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/generic/simple-card-utils.c

@@ -283,12 +283,20 @@ static int asoc_simple_card_get_dai_id(struct device_node *ep)
 	/* use endpoint/port reg if exist */
 	ret = of_graph_parse_endpoint(ep, &info);
 	if (ret == 0) {
-		if (info.id)
+		/*
+		 * Because it will count port/endpoint if it doesn't have "reg".
+		 * But, we can't judge whether it has "no reg", or "reg = <0>"
+		 * only of_graph_parse_endpoint().
+		 * We need to check "reg" property
+		 */
+		if (of_get_property(ep,   "reg", NULL))
 			return info.id;
-		if (info.port)
+
+		node = of_get_parent(ep);
+		of_node_put(node);
+		if (of_get_property(node, "reg", NULL))
 			return info.port;
 	}
-
 	node = of_graph_get_port_parent(ep);
 
 	/*