[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/synth/emux/emux_proc.c b/sound/synth/emux/emux_proc.c
index 58b9601..59144ec 100644
--- a/sound/synth/emux/emux_proc.c
+++ b/sound/synth/emux/emux_proc.c
@@ -128,10 +128,8 @@
 
 void snd_emux_proc_free(struct snd_emux *emu)
 {
-	if (emu->proc) {
-		snd_info_unregister(emu->proc);
-		emu->proc = NULL;
-	}
+	snd_info_free_entry(emu->proc);
+	emu->proc = NULL;
 }
 
 #endif /* CONFIG_PROC_FS */