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/cmipci.c b/sound/pci/cmipci.c
index 266c4cf..ff55257 100644
--- a/sound/pci/cmipci.c
+++ b/sound/pci/cmipci.c
@@ -2976,7 +2976,7 @@ static int snd_cmipci_create(struct snd_card *card, struct pci_dev *pci,
 {
 	struct cmipci *cm;
 	int err;
-	static struct snd_device_ops ops = {
+	static const struct snd_device_ops ops = {
 		.dev_free =	snd_cmipci_dev_free,
 	};
 	unsigned int val;