ASoC: Intel: Add build support for Baytrail SST

Enable build support for Baytrail SST DSP platform and byt-rt5640 machine
drivers.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Liam Girdwood <liam.r.girdwood@intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/intel/Kconfig b/sound/soc/intel/Kconfig
index ce5a692..274af16 100644
--- a/sound/soc/intel/Kconfig
+++ b/sound/soc/intel/Kconfig
@@ -27,6 +27,9 @@
 config SND_SOC_INTEL_HASWELL
 	tristate
 
+config SND_SOC_INTEL_BAYTRAIL
+	tristate
+
 config SND_SOC_INTEL_HASWELL_MACH
         tristate "ASoC Audio DSP support for Intel Haswell Lynxpoint"
         depends on SND_SOC_INTEL_SST && X86_INTEL_LPSS
@@ -36,4 +39,13 @@
           This adds support for the Lynxpoint Audio DSP on Intel(R) Haswell
 	  Ultrabook platforms.
           Say Y if you have such a device
-          If unsure select "N".
\ No newline at end of file
+          If unsure select "N".
+
+config SND_SOC_INTEL_BYT_RT5640_MACH
+	tristate "ASoC Audio driver for Intel Baytrail with RT5640 codec"
+	depends on SND_SOC_INTEL_SST && X86_INTEL_LPSS
+	select SND_SOC_INTEL_BAYTRAIL
+	select SND_SOC_RT5640
+	help
+	  This adds audio driver for Intel Baytrail platform based boards
+	  with the RT5640 audio codec.