ASoC: sound/wm9090: add missing __devexit marker

This fixes the following warning:

sound/soc/codecs/wm9090.c:668:12: warning: 'wm9090_i2c_remove' defined but not used
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/soc/codecs/wm9090.c

@@ -665,7 +665,7 @@ static int wm9090_i2c_probe(struct i2c_client *i2c,
 	return ret;
 }
 
-static int wm9090_i2c_remove(struct i2c_client *i2c)
+static int __devexit wm9090_i2c_remove(struct i2c_client *i2c)
 {
 	struct wm9090_priv *wm9090 = i2c_get_clientdata(i2c);