ALSA: usb-audio: add implicit fb quirk for Behringer UFX1204

Add quirk to ensure a sync endpoint is properly configured.
This patch is a fix for same symptoms on Behringer UFX1204 as patch
from Albertto Aquirre on Dec 8 2016 for Axe-Fx II.

Signed-off-by: Lassi Ylikojola <lassi.ylikojola@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index b9c9a19..3cbfae6 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -357,6 +357,15 @@ static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
 
 		alts = &iface->altsetting[1];
 		goto add_sync_ep;
+	case USB_ID(0x1397, 0x0002):
+		ep = 0x81;
+		iface = usb_ifnum_to_if(dev, 1);
+
+		if (!iface || iface->num_altsetting == 0)
+			return -EINVAL;
+
+		alts = &iface->altsetting[1];
+		goto add_sync_ep;
 
 	}
 	if (attr == USB_ENDPOINT_SYNC_ASYNC &&