[ALSA] usbusx2yaudio: kfree(NULL) is valid

if (!x) kfree(x); is not needed since kfree(NULL) is valid.
Signed-off-by: Richard Knutsson <ricknu-0@student.ltu.se>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/usb/usx2y/usbusx2yaudio.c

@@ -935,10 +935,9 @@ static struct snd_pcm_ops snd_usX2Y_pcm_ops =
  */
 static void usX2Y_audio_stream_free(struct snd_usX2Y_substream **usX2Y_substream)
 {
-	if (NULL != usX2Y_substream[SNDRV_PCM_STREAM_PLAYBACK]) {
 	kfree(usX2Y_substream[SNDRV_PCM_STREAM_PLAYBACK]);
 	usX2Y_substream[SNDRV_PCM_STREAM_PLAYBACK] = NULL;
-	}
+
 	kfree(usX2Y_substream[SNDRV_PCM_STREAM_CAPTURE]);
 	usX2Y_substream[SNDRV_PCM_STREAM_CAPTURE] = NULL;
 }