ALSA: usb-audio: Add TLV to M-Audio Fast Track Ultra controls

This adds db gain information to M-Audio Fast Track Ultra (8R) devices.

Signed-off-by: Felix Homann <linuxaudio@showlabor.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 1c3da65..045a0d9f 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -594,7 +594,7 @@
 				in  + 1, out + 1);
 			err = snd_create_std_mono_ctl(mixer, id, control,
 							cmask, val_type, name,
-							NULL);
+							&snd_usb_mixer_vol_tlv);
 			if (err < 0)
 				return err;
 		}
@@ -605,7 +605,7 @@
 				in - 7, out + 1);
 			err = snd_create_std_mono_ctl(mixer, id, control,
 							cmask, val_type, name,
-							NULL);
+							&snd_usb_mixer_vol_tlv);
 			if (err < 0)
 				return err;
 		}