ALSA: sparc: 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/20200103081714.9560-17-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/sparc/amd7930.c

@@ -912,7 +912,7 @@ static int snd_amd7930_dev_free(struct snd_device *device)
 	return snd_amd7930_free(amd);
 }
 
-static struct snd_device_ops snd_amd7930_dev_ops = {
+static const struct snd_device_ops snd_amd7930_dev_ops = {
 	.dev_free	=	snd_amd7930_dev_free,
 };
 

sound/sparc/cs4231.c

@@ -1771,7 +1771,7 @@ static int snd_cs4231_sbus_dev_free(struct snd_device *device)
 	return snd_cs4231_sbus_free(cp);
 }
 
-static struct snd_device_ops snd_cs4231_sbus_dev_ops = {
+static const struct snd_device_ops snd_cs4231_sbus_dev_ops = {
 	.dev_free	=	snd_cs4231_sbus_dev_free,
 };
 
@@ -1937,7 +1937,7 @@ static int snd_cs4231_ebus_dev_free(struct snd_device *device)
 	return snd_cs4231_ebus_free(cp);
 }
 
-static struct snd_device_ops snd_cs4231_ebus_dev_ops = {
+static const struct snd_device_ops snd_cs4231_ebus_dev_ops = {
 	.dev_free	=	snd_cs4231_ebus_dev_free,
 };