new ad1836 codec driver based on asoc

There has been an ad1836 driver in sound/blackfin based on traditional alsa.
The new driver is based on asoc. The architecture of ad1836 codec driver is
very much like ad1938.

Signed-off-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 31a6d21..05e2279 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -68,6 +68,9 @@
 	tristate
 	select SND_AC97_CODEC
 
+config SND_SOC_AD1836
+	tristate
+
 config SND_SOC_AD1938
 	tristate