ASoC: add snd_soc_of_get_dai_name() default of_xlate

Current snd_soc_of_get_dai_name() needs .of_xlate_dai_name()
callback on each component drivers.
But required behavior on almost all these drivers is
just returns its indexed driver's name.

This patch adds this feature as default behavior.
.of_xlate_dai_name() can overwrite it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index b13eecb..6ed3dc0 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -644,10 +644,12 @@
 struct snd_soc_component {
 	const char *name;
 	int id;
-	int num_dai;
 	struct device *dev;
 	struct list_head list;
 
+	struct snd_soc_dai_driver *dai_drv;
+	int num_dai;
+
 	const struct snd_soc_component_driver *driver;
 };