Driver core: convert sound core to use struct device

Converts from using struct "class_device" to "struct device" making
everything show up properly in /sys/devices/ with symlinks from the
/sys/class directory.

It also makes the struct sound_card to show up as a "real" device
where all the different sound class devices are placed as childs
and different card attribute files can hang off of. /sys/class/sound is
still a flat directory, but the symlink targets of all devices belonging
to the same card, point the the /sys/devices tree below the new card
device object.

Thanks to Kay for the updates to this patch.

Signed-off-by: Kay Sievers <kay.sievers@novell.com>
Acked-by: Jaroslav Kysela <perex@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/sound/core/init.c b/sound/core/init.c
index 3058d62..6152a75 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -361,6 +361,8 @@
 		snd_printk(KERN_WARNING "unable to free card info\n");
 		/* Not fatal error */
 	}
+	if (card->dev)
+		device_unregister(card->dev);
 	kfree(card);
 	return 0;
 }
@@ -495,6 +497,12 @@
 	int err;
 
 	snd_assert(card != NULL, return -EINVAL);
+	if (!card->dev) {
+		card->dev = device_create(sound_class, card->parent, 0,
+					  "card%i", card->number);
+		if (IS_ERR(card->dev))
+			card->dev = NULL;
+	}
 	if ((err = snd_device_register_all(card)) < 0)
 		return err;
 	mutex_lock(&snd_card_mutex);