ALSA: rme9652: 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/20191210063454.31603-34-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/rme9652/hdsp.c

@@ -5233,6 +5233,7 @@ static int snd_hdsp_create(struct snd_card *card,
 	}
 
 	hdsp->irq = pci->irq;
+	card->sync_irq = hdsp->irq;
 	hdsp->precise_ptr = 0;
 	hdsp->use_midi_tasklet = 1;
 	hdsp->dds_value = 0;

sound/pci/rme9652/hdspm.c

@@ -6613,6 +6613,7 @@ static int snd_hdspm_create(struct snd_card *card,
 	dev_dbg(card->dev, "use IRQ %d\n", pci->irq);
 
 	hdspm->irq = pci->irq;
+	card->sync_irq = hdspm->irq;
 
 	dev_dbg(card->dev, "kmalloc Mixer memory of %zd Bytes\n",
 		sizeof(*hdspm->mixer));

sound/pci/rme9652/rme9652.c

@@ -2479,6 +2479,7 @@ static int snd_rme9652_create(struct snd_card *card,
 		return -EBUSY;
 	}
 	rme9652->irq = pci->irq;
+	card->sync_irq = rme9652->irq;
 	rme9652->precise_ptr = precise_ptr;
 
 	/* Determine the h/w rev level of the card. This seems like