staging: bcm2835-audio: Drop useless NULL check

alsa_stream->chip can be never NULL.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -188,8 +188,7 @@ static int snd_bcm2835_playback_close(struct snd_pcm_substream *substream)
 	alsa_stream->buffer_size = 0;
 
 	bcm2835_audio_close(alsa_stream);
-	if (alsa_stream->chip)
-		alsa_stream->chip->alsa_stream[alsa_stream->idx] = NULL;
+	alsa_stream->chip->alsa_stream[alsa_stream->idx] = NULL;
 	/*
 	 * Do not free up alsa_stream here, it will be freed up by
 	 * runtime->private_free callback we registered in *_open above