ASoC: simple-card-utils: add asoc_simple_card_of_parse_widgets()

Current simple card drivers are parsing widgets on each own driver
(only simple-card at this point, but will be supported on all drivers)
Encapsulation is one of simple card util's purpose.
Let's add asoc_simple_card_of_parse_widgets for it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/sound/simple_card_utils.h b/include/sound/simple_card_utils.h
index 889c8ff..42c6a6a 100644
--- a/include/sound/simple_card_utils.h
+++ b/include/sound/simple_card_utils.h
@@ -103,5 +103,7 @@ void asoc_simple_card_parse_convert(struct device *dev, char *prefix,
 int asoc_simple_card_of_parse_routing(struct snd_soc_card *card,
 				      char *prefix,
 				      int optional);
+int asoc_simple_card_of_parse_widgets(struct snd_soc_card *card,
+				      char *prefix);
 
 #endif /* __SIMPLE_CARD_UTILS_H */