ALSA: ali5451: remove irq enabling in pointer callback

snd_ali_pointer function is called with local
interrupts disabled. However it seems very strange to
reenable them in such way.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Denis Efremov <yefremov.denis@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ali5451/ali5451.c

@@ -1435,7 +1435,7 @@ static snd_pcm_uframes_t snd_ali_pointer(struct snd_pcm_substream *substream)
 
 	spin_lock(&codec->reg_lock);
 	if (!pvoice->running) {
-		spin_unlock_irq(&codec->reg_lock);
+		spin_unlock(&codec->reg_lock);
 		return 0;
 	}
 	outb(pvoice->number, ALI_REG(codec, ALI_GC_CIR));