ALSA: rme96: 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/20191210063454.31603-33-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/rme96.c

@@ -1629,6 +1629,7 @@ snd_rme96_create(struct rme96 *rme96)
 		return -EBUSY;
 	}
 	rme96->irq = pci->irq;
+	rme96->card->sync_irq = rme96->irq;
 
 	/* read the card's revision number */
 	pci_read_config_byte(pci, 8, &rme96->rev);