ALSA: xen: Drop superfluous ioctl PCM ops

PCM core deals the empty ioctl field now as default(*).
Let's kill the redundant lines.

(*) commit fc033cbf ("ALSA: pcm: Allow NULL ioctl ops")

Link: https://lore.kernel.org/r/20191210061145.24641-24-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/xen/xen_snd_front_alsa.c

@@ -692,7 +692,6 @@ static int alsa_pb_fill_silence(struct snd_pcm_substream *substream,
 static const struct snd_pcm_ops snd_drv_alsa_playback_ops = {
 	.open		= alsa_open,
 	.close		= alsa_close,
-	.ioctl		= snd_pcm_lib_ioctl,
 	.hw_params	= alsa_hw_params,
 	.hw_free	= alsa_hw_free,
 	.prepare	= alsa_prepare,
@@ -706,7 +705,6 @@ static const struct snd_pcm_ops snd_drv_alsa_playback_ops = {
 static const struct snd_pcm_ops snd_drv_alsa_capture_ops = {
 	.open		= alsa_open,
 	.close		= alsa_close,
-	.ioctl		= snd_pcm_lib_ioctl,
 	.hw_params	= alsa_hw_params,
 	.hw_free	= alsa_hw_free,
 	.prepare	= alsa_prepare,