ALSA: ad1889: Support PCM sync_stop

The driver invokes snd_pcm_period_elapsed() simply from the interrupt
handler.  Set card->sync_irq for enabling the missing sync_stop PCM
operation.

Link: https://lore.kernel.org/r/20191210063454.31603-2-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ad1889.c

@@ -899,7 +899,7 @@ snd_ad1889_create(struct snd_card *card,
 	}
 
 	chip->irq = pci->irq;
-	synchronize_irq(chip->irq);
+	card->sync_irq = chip->irq;
 
 	/* (2) initialization of the chip hardware */
 	if ((err = snd_ad1889_init(chip)) < 0) {