staging: greybus: audio_codec: Remove useless return statement.

Remove return statement that is immediately followed by the function
closing bracket.

Signed-off-by: Elise Lennion <elise.lennion@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/audio_codec.c

@@ -405,7 +405,6 @@ static void gbcodec_shutdown(struct snd_pcm_substream *substream,
 	params->state = GBAUDIO_CODEC_SHUTDOWN;
 	mutex_unlock(&codec->lock);
 	pm_relax(dai->dev);
-	return;
 }
 
 static int gbcodec_hw_params(struct snd_pcm_substream *substream,