ALSA: control: Embed struct device

This patch embeds a struct device for the control device into the card
object and avoid the device creation at registration time.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/core.h

@@ -109,6 +109,7 @@ struct snd_card {
 								private data */
 	struct list_head devices;	/* devices */
 
+	struct device ctl_dev;		/* control device */
 	unsigned int last_numid;	/* last used numeric ID */
 	struct rw_semaphore controls_rwsem;	/* controls list lock */
 	rwlock_t ctl_files_rwlock;	/* ctl_files list lock */