[ALSA] ad1816a - Add clockfreq module option

Documentation,AD1816A driver
Added clockfreq module option for the card with a different clock frequency
than 33kHz.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/include/sound/ad1816a.h b/include/sound/ad1816a.h
index 395978e..ca2e0e4 100644
--- a/include/sound/ad1816a.h
+++ b/include/sound/ad1816a.h
@@ -138,6 +138,7 @@
 	spinlock_t lock;
 
 	unsigned short mode;
+	unsigned int clock_freq;
 
 	snd_card_t *card;
 	snd_pcm_t *pcm;