ASoC: kirkwood: combine kirkwood-i2s and kirkwood-dma drivers

These really should be a single driver because they're fully integrated
in hardware.  Make them so.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/kirkwood/kirkwood.h b/sound/soc/kirkwood/kirkwood.h
index 9a50607..1d13dee 100644
--- a/sound/soc/kirkwood/kirkwood.h
+++ b/sound/soc/kirkwood/kirkwood.h
@@ -138,4 +138,6 @@
 	int burst;
 };
 
+extern struct snd_soc_platform_driver kirkwood_soc_platform;
+
 #endif