ipc4: stream: add container format for ipc4

Sample format is alway equal to container format for
ipc3 case but it is not true for ipc4, .e.g sample format
is S16_LE but container format will be S32_LE. This patch
adds container_fmt for ipc4 to do stream copy.

Signed-off-by: Rander Wang <rander.wang@intel.com>

src/include/sof/audio/audio_stream.h

@@ -54,6 +54,8 @@ struct audio_stream {
 
 	/* runtime stream params */
 	enum sof_ipc_frame frame_fmt;	/**< Sample data format */
+	enum sof_ipc_frame valid_sample_fmt;
+
 	uint32_t rate;		/**< Number of data frames per second [Hz] */
 	uint16_t channels;	/**< Number of samples in each frame */