ASoC: sta529: Staticise non-exported codec driver struct

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/sta529.c b/sound/soc/codecs/sta529.c
index 0c225cd..9e31448 100644
--- a/sound/soc/codecs/sta529.c
+++ b/sound/soc/codecs/sta529.c
@@ -358,7 +358,7 @@
 	return 0;
 }
 
-struct snd_soc_codec_driver sta529_codec_driver = {
+static const struct snd_soc_codec_driver sta529_codec_driver = {
 	.probe = sta529_probe,
 	.remove = sta529_remove,
 	.set_bias_level = sta529_set_bias_level,