ALSA: ymfpci: 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/20191210063454.31603-39-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ymfpci/ymfpci_main.c

@@ -2371,6 +2371,7 @@ int snd_ymfpci_create(struct snd_card *card,
 		goto free_chip;
 	}
 	chip->irq = pci->irq;
+	card->sync_irq = chip->irq;
 
 	snd_ymfpci_aclink_reset(pci);
 	if (snd_ymfpci_codec_ready(chip, 0) < 0) {