ALSA: Remove struct snd_monitor_file from public sound/core.h

The struct snd_monitor_file is used locally only in sound/core/init.c,
thus it should be moved there from the public sound/core.h.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/init.c b/sound/core/init.c
index d5d40d7..ec4a50c 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -31,6 +31,14 @@
 #include <sound/control.h>
 #include <sound/info.h>
 
+/* monitor files for graceful shutdown (hotplug) */
+struct snd_monitor_file {
+	struct file *file;
+	const struct file_operations *disconnected_f_op;
+	struct list_head shutdown_list;	/* still need to shutdown */
+	struct list_head list;	/* link of monitor files */
+};
+
 static DEFINE_SPINLOCK(shutdown_lock);
 static LIST_HEAD(shutdown_files);