sound: usb: make the USB MIDI module more independent

Remove the dependecy from the USB MIDI code on the snd_usb_audio
structure.  This allows using the USB MIDI module from another driver
without having to pretend to be the generic USB audio driver.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/usx2y/usX2Yhwdep.c b/sound/usb/usx2y/usX2Yhwdep.c
index 52e04b2..f96ab86 100644
--- a/sound/usb/usx2y/usX2Yhwdep.c
+++ b/sound/usb/usx2y/usX2Yhwdep.c
@@ -171,7 +171,7 @@
 		&quirk_2 : &quirk_1;
 
 	snd_printdd("usX2Y_create_usbmidi \n");
-	return snd_usb_create_midi_interface(&usX2Y(card)->chip, iface, quirk);
+	return snd_usbmidi_create(card, iface, &usX2Y(card)->midi_list, quirk);
 }
 
 static int usX2Y_create_alsa_devices(struct snd_card *card)