ALSA: midi: constify snd_rawmidi_global_ops structures

---
 include/sound/rawmidi.h      | 2 +-
 sound/core/seq/seq_virmidi.c | 2 +-
 sound/usb/midi.c             | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)
 
diff --git a/include/sound/rawmidi.h b/include/sound/rawmidi.h
index f6cbef7..fdabbb4 100644
--- a/include/sound/rawmidi.h
+++ b/include/sound/rawmidi.h
@@ -130,7 +130,7 @@ struct snd_rawmidi {
 	int ossreg;
 #endif
 
-	struct snd_rawmidi_global_ops *ops;
+	const struct snd_rawmidi_global_ops *ops;
 
 	struct snd_rawmidi_str streams[2];
 
diff --git a/sound/core/seq/seq_virmidi.c b/sound/core/seq/seq_virmidi.c
index 56e0f4cd..3da2d48 100644
--- a/sound/core/seq/seq_virmidi.c
+++ b/sound/core/seq/seq_virmidi.c
@@ -468,7 +468,7 @@ static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
 /*
  *
  */
-static struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
+static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
 	.dev_register = snd_virmidi_dev_register,
 	.dev_unregister = snd_virmidi_dev_unregister,
 };
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index 5b4c58c..ee212e7 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -2206,7 +2206,7 @@ static int snd_usbmidi_create_endpoints_midiman(struct snd_usb_midi *umidi,
 	return 0;
 }
 
-static struct snd_rawmidi_global_ops snd_usbmidi_ops = {
+static const struct snd_rawmidi_global_ops snd_usbmidi_ops = {
 	.get_port_info = snd_usbmidi_get_port_info,
 };