ASoC: rcar ctu: Staticise local symbols

rsnd_of_parse_ctu() is not used outside this file so it can be static.
Fixes the following sparse warning:

	sound/soc/sh/rcar/ctu.c:72:6: warning: symbol 'rsnd_of_parse_ctu' was
		not declared. Should it be static?

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/ctu.c

@@ -69,7 +69,7 @@ struct rsnd_mod *rsnd_ctu_mod_get(struct rsnd_priv *priv, int id)
 	return &((struct rsnd_ctu *)(priv->ctu) + id)->mod;
 }
 
-void rsnd_of_parse_ctu(struct platform_device *pdev,
+static void rsnd_of_parse_ctu(struct platform_device *pdev,
 		       const struct rsnd_of_data *of_data,
 		       struct rsnd_priv *priv)
 {