ALSA: msnd: 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/isa/msnd/msnd.c

@@ -572,7 +572,7 @@ snd_msnd_playback_pointer(struct snd_pcm_substream *substream)
 }
 
 
-static struct snd_pcm_ops snd_msnd_playback_ops = {
+static const struct snd_pcm_ops snd_msnd_playback_ops = {
 	.open =		snd_msnd_playback_open,
 	.close =	snd_msnd_playback_close,
 	.ioctl =	snd_pcm_lib_ioctl,
@@ -669,7 +669,7 @@ static int snd_msnd_capture_hw_params(struct snd_pcm_substream *substream,
 }
 
 
-static struct snd_pcm_ops snd_msnd_capture_ops = {
+static const struct snd_pcm_ops snd_msnd_capture_ops = {
 	.open =		snd_msnd_capture_open,
 	.close =	snd_msnd_capture_close,
 	.ioctl =	snd_pcm_lib_ioctl,