ALSA: pci: Constify snd_device_ops definitions

Now we may declare const for snd_device_ops definitions, so let's do
it for optimization.

There should be no functional changes by this patch.

Link: https://lore.kernel.org/r/20200103081714.9560-10-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/via82xx.c b/sound/pci/via82xx.c
index e72050a..090b0c4 100644
--- a/sound/pci/via82xx.c
+++ b/sound/pci/via82xx.c
@@ -2332,7 +2332,7 @@ static int snd_via82xx_create(struct snd_card *card,
 {
 	struct via82xx *chip;
 	int err;
-        static struct snd_device_ops ops = {
+	static const struct snd_device_ops ops = {
 		.dev_free =	snd_via82xx_dev_free,
         };