staging: bcm2835-audio: Deliver indirect-PCM transfer error

Now that the indirect-PCM transfer helper gives back an error, we
should return the error from ack callbacks.
Acked-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c

@@ -353,9 +353,8 @@ static int snd_bcm2835_pcm_ack(struct snd_pcm_substream *substream)
 	struct snd_pcm_indirect *pcm_indirect = &alsa_stream->pcm_indirect;
 
 	pcm_indirect->hw_queue_size = runtime->hw.buffer_bytes_max;
-	snd_pcm_indirect_playback_transfer(substream, pcm_indirect,
-					   snd_bcm2835_pcm_transfer);
-	return 0;
+	return snd_pcm_indirect_playback_transfer(substream, pcm_indirect,
+						  snd_bcm2835_pcm_transfer);
 }
 
 /* trigger callback */