[ALSA] opl3 - Fix build errors

I applied a wrong patch for 'opl3 - simplify exclusive access lock'.
Fixed now.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/include/sound/opl3.h b/include/sound/opl3.h
index eea584b..d7e33ce 100644
--- a/include/sound/opl3.h
+++ b/include/sound/opl3.h
@@ -318,6 +318,7 @@
 	void *private_data;
 	void (*private_free)(struct snd_opl3 *);
 
+	struct snd_hwdep *hwdep;
 	spinlock_t reg_lock;
 	struct snd_card *card;		/* The card that this belongs to */
 	unsigned char fm_mode;		/* OPL mode, see SNDRV_DM_FM_MODE_XXX */