ASoC: pcm: Add pcm operation for pcm ioctl.

Provide an ioctl marshaller for ASoC platform drivers.
This will use the default ALSA handler if no platform
handler exists.

This is also required for DPCM BE PCMs as snd_pcm_info()
will call the ioctl as part of stream startup.
Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-pcm.c

@@ -1647,6 +1647,17 @@ int dpcm_fe_dai_prepare(struct snd_pcm_substream *substream)
 	return ret;
 }
 
+static int soc_pcm_ioctl(struct snd_pcm_substream *substream,
+		     unsigned int cmd, void *arg)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_platform *platform = rtd->platform;
+
+	if (platform->driver->ops->ioctl)
+		return platform->driver->ops->ioctl(substream, cmd, arg);
+	return snd_pcm_lib_ioctl(substream, cmd, arg);
+}
+
 static int dpcm_run_update_shutdown(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_pcm_substream *substream =
@@ -2051,6 +2062,7 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
 		rtd->ops.hw_free	= dpcm_fe_dai_hw_free;
 		rtd->ops.close		= dpcm_fe_dai_close;
 		rtd->ops.pointer	= soc_pcm_pointer;
+		rtd->ops.ioctl		= soc_pcm_ioctl;
 	} else {
 		rtd->ops.open		= soc_pcm_open;
 		rtd->ops.hw_params	= soc_pcm_hw_params;
@@ -2059,6 +2071,7 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
 		rtd->ops.hw_free	= soc_pcm_hw_free;
 		rtd->ops.close		= soc_pcm_close;
 		rtd->ops.pointer	= soc_pcm_pointer;
+		rtd->ops.ioctl		= soc_pcm_ioctl;
 	}
 
 	if (platform->driver->ops) {