ALSA: asihpi: fix sign bug

bytes_per_sec is unsigned, so if snd_pcm_format_width() return error we
would not see it.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/asihpi/asihpi.c b/sound/pci/asihpi/asihpi.c
index 91218f7..c80b0b8 100644
--- a/sound/pci/asihpi/asihpi.c
+++ b/sound/pci/asihpi/asihpi.c
@@ -460,6 +460,7 @@
 	struct snd_card_asihpi *card = snd_pcm_substream_chip(substream);
 	int err;
 	u16 format;
+	int width;
 	unsigned int bytes_per_sec;
 
 	print_hwparams(params);
@@ -512,9 +513,10 @@
 				dpcm->hpi_buffer_attached);
 	}
 	bytes_per_sec = params_rate(params) * params_channels(params);
-	bytes_per_sec *= snd_pcm_format_width(params_format(params));
+	width = snd_pcm_format_width(params_format(params));
+	bytes_per_sec *= width;
 	bytes_per_sec /= 8;
-	if (bytes_per_sec <= 0)
+	if (width < 0 || bytes_per_sec == 0)
 		return -EINVAL;
 
 	dpcm->bytes_per_sec = bytes_per_sec;