ALSA: atmel: constify snd_pcm_ops structures

snd_pcm_ops are not supposed to change at runtime. All functions
working with snd_pcm_ops provided by <sound/pcm.h> work with
const snd_pcm_ops. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/atmel/ac97c.c

@@ -461,7 +461,7 @@ atmel_ac97c_capture_pointer(struct snd_pcm_substream *substream)
 	return frames;
 }
 
-static struct snd_pcm_ops atmel_ac97_playback_ops = {
+static const struct snd_pcm_ops atmel_ac97_playback_ops = {
 	.open		= atmel_ac97c_playback_open,
 	.close		= atmel_ac97c_playback_close,
 	.ioctl		= snd_pcm_lib_ioctl,
@@ -472,7 +472,7 @@ static struct snd_pcm_ops atmel_ac97_playback_ops = {
 	.pointer	= atmel_ac97c_playback_pointer,
 };
 
-static struct snd_pcm_ops atmel_ac97_capture_ops = {
+static const struct snd_pcm_ops atmel_ac97_capture_ops = {
 	.open		= atmel_ac97c_capture_open,
 	.close		= atmel_ac97c_capture_close,
 	.ioctl		= snd_pcm_lib_ioctl,