[ALSA] ASoC export AC97 DAI

This patch exports the ASoC AC97 Digital Audio Interface as a GPL'ed
symbol.

Signed-off-by: Graeme Gregory <gg@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lg@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/soc/codecs/ac97.h b/sound/soc/codecs/ac97.h
index 930ddfc..2bf6d69 100644
--- a/sound/soc/codecs/ac97.h
+++ b/sound/soc/codecs/ac97.h
@@ -14,5 +14,6 @@
 #define __LINUX_SND_SOC_AC97_H
 
 extern struct snd_soc_codec_device soc_codec_dev_ac97;
+extern struct snd_soc_codec_dai ac97_dai;
 
 #endif