ASoC: zx: zx_i2s_dai can be static

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/zte/zx296702-i2s.c b/sound/soc/zte/zx296702-i2s.c
index cf6005c..472fde3 100644
--- a/sound/soc/zte/zx296702-i2s.c
+++ b/sound/soc/zte/zx296702-i2s.c
@@ -355,7 +355,7 @@
 	.name			= "zx-i2s",
 };
 
-struct snd_soc_dai_driver zx_i2s_dai = {
+static struct snd_soc_dai_driver zx_i2s_dai = {
 	.name	= "zx-i2s-dai",
 	.id	= 0,
 	.probe	= zx_i2s_dai_probe,