ASoC: Staticise workqueue function for GPIO jack detection

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/soc-jack.c b/sound/soc/soc-jack.c
index bdf2484..28346fb 100644
--- a/sound/soc/soc-jack.c
+++ b/sound/soc/soc-jack.c
@@ -143,7 +143,7 @@
 
 #ifdef CONFIG_GPIOLIB
 /* gpio detect */
-void snd_soc_jack_gpio_detect(struct snd_soc_jack_gpio *gpio)
+static void snd_soc_jack_gpio_detect(struct snd_soc_jack_gpio *gpio)
 {
 	struct snd_soc_jack *jack = gpio->jack;
 	int enable;