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/include/sound/soc.h b/include/sound/soc.h
index 71e0c05..a7bc82b 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -440,7 +440,9 @@
 int snd_soc_platform_write(struct snd_soc_platform *platform,
 					unsigned int reg, unsigned int val);
 int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num);
-int soc_new_compress(struct snd_soc_pcm_runtime *rtd, int num);
+#ifdef CONFIG_SND_SOC_COMPRESS
+int snd_soc_new_compress(struct snd_soc_pcm_runtime *rtd, int num);
+#endif
 
 struct snd_pcm_substream *snd_soc_get_dai_substream(struct snd_soc_card *card,
 		const char *dai_link, int stream);