ASoC: topology: ABI - Add sig_bits to stream caps

Kernel struct snd_soc_pcm_stream, SoC PCM stream information, needs this
field. Although current topology users don't configure this, we define it
for future extension.
Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

include/uapi/sound/asoc.h

@@ -257,6 +257,7 @@ struct snd_soc_tplg_stream_caps {
 	__le32 period_size_max;	/* max period size bytes */
 	__le32 buffer_size_min;	/* min buffer size bytes */
 	__le32 buffer_size_max;	/* max buffer size bytes */
+	__le32 sig_bits;        /* number of bits of content */
 } __attribute__((packed));
 
 /*

sound/soc/soc-topology.c

@@ -1556,6 +1556,7 @@ static void set_stream_info(struct snd_soc_pcm_stream *stream,
 	stream->rate_min = caps->rate_min;
 	stream->rate_max = caps->rate_max;
 	stream->formats = caps->formats;
+	stream->sig_bits = caps->sig_bits;
 }
 
 static void set_dai_flags(struct snd_soc_dai_driver *dai_drv,