ALSA: sparc/cs4231: Use WARN_ON() instead of BUG_ON()

BUG_ON() is rather useless for debugging as it leads to panic().
Use WARN_ON() and handle the error cases accordingly.

Signed-off-by: Takashi Iwai <[e-mail]>

sound/sparc/cs4231.c

···
 		unsigned int period_size = snd_pcm_lib_period_bytes(substream);
 		unsigned int offset = period_size * (*periods_sent);
 
-		BUG_ON(period_size >= (1 << 24));
+		if (WARN_ON(period_size >= (1 << 24)))
+			return;
 
 		if (dma_cont->request(dma_cont,
 				      runtime->dma_addr + offset, period_size))
···
 	chip->image[CS4231_IFACE_CTRL] &= ~(CS4231_PLAYBACK_ENABLE |
 					    CS4231_PLAYBACK_PIO);
 
-	BUG_ON(runtime->period_size > 0xffff + 1);
+	if (WARN_ON(runtime->period_size > 0xffff + 1))
+		return -EINVAL;
 
 	chip->p_periods_sent = 0;
 	spin_unlock_irqrestore(&chip->lock, flags);