ASoC: sunxi: Add Allwinner A10 Digital Audio driver

The Allwinner A10 and later come with a hardware block that used for the
PCM and I2S interfaces.

Add a driver for it in ASoC.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Tested-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/sunxi/Makefile b/sound/soc/sunxi/Makefile
index 8f5e889..604c7b84 100644
--- a/sound/soc/sunxi/Makefile
+++ b/sound/soc/sunxi/Makefile
@@ -1,3 +1,3 @@
 obj-$(CONFIG_SND_SUN4I_CODEC) += sun4i-codec.o
-
+obj-$(CONFIG_SND_SUN4I_I2S) += sun4i-i2s.o
 obj-$(CONFIG_SND_SUN4I_SPDIF) += sun4i-spdif.o