ALSA: usb-audio: Correct the return code from snd_usb_endpoint_set_params()

snd_usb_endpoint_set_params() should return zero for a success, but
currently it returns the sample rate.  Correct it.

Fixes: 2be79d586454 ("ALSA: usb-audio: Split endpoint setups for hw_params and prepare (take#2)")
Link: https://lore.kernel.org/r/20221009104212.18877-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index da378e5..44cce6c 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -1386,6 +1386,8 @@ int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
 
 	err = update_clock_ref_rate(chip, ep);
+	if (err >= 0)
+		err = 0;
  unlock:
 	mutex_unlock(&chip->mutex);
 	return err;