ALSA: sis7019: 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/20191210063454.31603-35-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/sis7019.c

@@ -1335,6 +1335,7 @@ static int sis_chip_create(struct snd_card *card,
 	}
 
 	sis->irq = pci->irq;
+	card->sync_irq = sis->irq;
 	pci_set_master(pci);
 
 	for (i = 0; i < 64; i++) {