ALSA: wss: 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/20191210063454.31603-49-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/wss/wss_lib.c

@@ -1811,6 +1811,7 @@ int snd_wss_create(struct snd_card *card,
 			return -EBUSY;
 		}
 	chip->irq = irq;
+	card->sync_irq = chip->irq;
 	if (!(hwshare & WSS_HWSHARE_DMA1) && request_dma(dma1, "WSS - 1")) {
 		snd_printk(KERN_ERR "wss: can't grab DMA1 %d\n", dma1);
 		snd_wss_free(chip);