arm: nvidia and smdk6400: use common code for machine type

NVIDIA boards and Samsung SMDK6400 already use a local variant of
CONFIG_MACH_TYPE option.
Switch to use the new common code.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/include/configs/smdk6400.h b/include/configs/smdk6400.h
index c9acf58..d175ed6 100644
--- a/include/configs/smdk6400.h
+++ b/include/configs/smdk6400.h
@@ -65,7 +65,7 @@
 /*
  * Architecture magic and machine type
  */
-#define MACH_TYPE		1270
+#define CONFIG_MACH_TYPE		1270
 
 #define CONFIG_DISPLAY_CPUINFO
 #define CONFIG_DISPLAY_BOARDINFO