ASoC: core: If a platform doesn't have an of_node use parent's node

Support was added to allow location of both CPU and CODEC components
of a DAI link from their parent's of_node if they did not have an
of_node themselves in this commit:

commit 3e0aa8d8 ("ASoC: core: If component doesn't have of_node
                      use parent's node instead")

However this leaves platforms as something of a special case as the
major DAI component that doesn't do this. Since this is useful for MFD
devices which often utilise a single device tree entry for the whole
device, add support for looking up platforms from the parent's of_node
as well.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-core.c

@@ -993,6 +993,7 @@ static int soc_bind_dai_link(struct snd_soc_card *card,
 	struct snd_soc_dai_link_component cpu_dai_component;
 	struct snd_soc_dai **codec_dais;
 	struct snd_soc_platform *platform;
+	struct device_node *platform_of_node;
 	const char *platform_name;
 	int i;
 
@@ -1042,9 +1043,12 @@ static int soc_bind_dai_link(struct snd_soc_card *card,
 
 	/* find one from the set of registered platforms */
 	list_for_each_entry(platform, &platform_list, list) {
+		platform_of_node = platform->dev->of_node;
+		if (!platform_of_node && platform->dev->parent->of_node)
+			platform_of_node = platform->dev->parent->of_node;
+
 		if (dai_link->platform_of_node) {
-			if (platform->dev->of_node !=
-			    dai_link->platform_of_node)
+			if (platform_of_node != dai_link->platform_of_node)
 				continue;
 		} else {
 			if (strcmp(platform->component.name, platform_name))