ALSA: xen-front: Refine indentations and constify snd_pcm_ops

snd_pcm_ops are not supposed to change. So mark the
non-const structs as const. Also, refine indentation
to ncrease readability.
Signed-off-by: Nick Simonov <nicksimonovv@gmail.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/xen/xen_snd_front_alsa.c

@@ -637,7 +637,7 @@ static int alsa_pb_fill_silence(struct snd_pcm_substream *substream,
  * to know when the buffer can be transferred to the backend.
  */
 
-static struct snd_pcm_ops snd_drv_alsa_playback_ops = {
+static const struct snd_pcm_ops snd_drv_alsa_playback_ops = {
 	.open		= alsa_open,
 	.close		= alsa_close,
 	.ioctl		= snd_pcm_lib_ioctl,
@@ -651,7 +651,7 @@ static struct snd_pcm_ops snd_drv_alsa_playback_ops = {
 	.fill_silence	= alsa_pb_fill_silence,
 };
 
-static struct snd_pcm_ops snd_drv_alsa_capture_ops = {
+static const struct snd_pcm_ops snd_drv_alsa_capture_ops = {
 	.open		= alsa_open,
 	.close		= alsa_close,
 	.ioctl		= snd_pcm_lib_ioctl,