ASoC: compress: add config item for soc-compress to make it compiled only when needed

We don't always need soc-compress in soc, here add a config item
SND_SOC_COMPRESS, when nobody select it, the soc-compress will
not be compiled.

Here also change Kconfig to 'select SND_SOC_COMPRESS' for drivers
that needed soc-compress.

Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
index 683e501..4c734f5 100644
--- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
+++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
@@ -529,7 +529,7 @@
 },
 {
 	.name = "compress-cpu-dai",
-	.compress_dai = 1,
+	.compress_new = snd_soc_new_compress,
 	.ops = &sst_compr_dai_ops,
 	.playback = {
 		.stream_name = "Compress Playback",