ASoC: cros_ec_codec: Make symbol 'cros_ec_dai' static

Fixes the following sparse warning:

sound/soc/codecs/cros_ec_codec.c:209:27: warning:
 symbol 'cros_ec_dai' was not declared. Should it be static?

Fixes: b291f42a ("ASoC: cros_ec_codec: Add codec driver for Cros EC")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cros_ec_codec.c

@@ -206,7 +206,7 @@ static const struct snd_soc_dai_ops cros_ec_i2s_dai_ops = {
 	.set_fmt = cros_ec_i2s_set_dai_fmt,
 };
 
-struct snd_soc_dai_driver cros_ec_dai[] = {
+static struct snd_soc_dai_driver cros_ec_dai[] = {
 	{
 		.name = "cros_ec_codec I2S",
 		.id = 0,