ALSA: asihpi: Kill BUG_ON() usages

BUG_ON() is the worst choice for a trivial sanity check.
Either it should be removed or replaced with a softer one like
WARN_ON() if still really needed.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/asihpi/asihpi.c

@@ -558,12 +558,10 @@ static void snd_card_asihpi_pcm_int_start(struct snd_pcm_substream *substream)
 	struct snd_card_asihpi_pcm *dpcm;
 	struct snd_card_asihpi *card;
 
-	BUG_ON(!substream);
-
 	dpcm = (struct snd_card_asihpi_pcm *)substream->runtime->private_data;
 	card = snd_pcm_substream_chip(substream);
 
-	BUG_ON(in_interrupt());
+	WARN_ON(in_interrupt());
 	tasklet_disable(&card->t);
 	card->llmode_streampriv = dpcm;
 	tasklet_enable(&card->t);
@@ -578,8 +576,6 @@ static void snd_card_asihpi_pcm_int_stop(struct snd_pcm_substream *substream)
 	struct snd_card_asihpi_pcm *dpcm;
 	struct snd_card_asihpi *card;
 
-	BUG_ON(!substream);
-
 	dpcm = (struct snd_card_asihpi_pcm *)substream->runtime->private_data;
 	card = snd_pcm_substream_chip(substream);