ASoC: Add dmaengine PCM helper functions

This patch adds a set of functions which are intended to be used when
implementing a dmaengine based sound PCM driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
index 35e662d..91c9855 100644
--- a/sound/soc/Kconfig
+++ b/sound/soc/Kconfig
@@ -25,6 +25,9 @@
 config SND_SOC_AC97_BUS
 	bool
 
+config SND_SOC_DMAENGINE_PCM
+	bool
+
 # All the supported SoCs
 source "sound/soc/atmel/Kconfig"
 source "sound/soc/au1x/Kconfig"