ASoC: SOF: add a flag suspend_ignored for sof stream

Add a suspend_ignored flag to snd_sof_pcm_stream that will be used to
decide if the corresponding FW pipeline should be kept active to perform
always on tasks when the system is entering the S0ix state.
Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191025224122.7718-21-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/sof-priv.h

@@ -311,6 +311,11 @@ struct snd_sof_pcm_stream {
 	struct snd_pcm_substream *substream;
 	struct work_struct period_elapsed_work;
 	bool d0i3_compatible; /* DSP can be in D0I3 when this pcm is opened */
+	/*
+	 * flag to indicate that the DSP pipelines should be kept
+	 * active or not while suspending the stream
+	 */
+	bool suspend_ignored;
 };
 
 /* ALSA SOF PCM device */