[ALSA] Fix disconnection of proc interface

- Add the linked list to each proc entry to enable a single-shot
  disconnection (unregister)
- Deprecate snd_info_unregister(), use snd_info_free_entry()
- Removed NULL checks of snd_info_free_entry()

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/core/sound_oss.c b/sound/core/sound_oss.c
index 74f0fe5..b2fc40a 100644
--- a/sound/core/sound_oss.c
+++ b/sound/core/sound_oss.c
@@ -270,8 +270,7 @@
 
 int __exit snd_minor_info_oss_done(void)
 {
-	if (snd_minor_info_oss_entry)
-		snd_info_unregister(snd_minor_info_oss_entry);
+	snd_info_free_entry(snd_minor_info_oss_entry);
 	return 0;
 }
 #endif /* CONFIG_PROC_FS */