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/board/nvidia/common/board.c b/board/nvidia/common/board.c
index 8ab9440..5eca5eb 100644
--- a/board/nvidia/common/board.c
+++ b/board/nvidia/common/board.c
@@ -318,8 +318,6 @@
 {
 	/* boot param addr */
 	gd->bd->bi_boot_params = (NV_PA_SDRAM_BASE + 0x100);
-	/* board id for Linux */
-	gd->bd->bi_arch_number = CONFIG_MACH_TYPE;
 
 	return 0;
 }
diff --git a/board/samsung/smdk6400/smdk6400.c b/board/samsung/smdk6400/smdk6400.c
index 13c7ed5..c40d1f9 100644
--- a/board/samsung/smdk6400/smdk6400.c
+++ b/board/samsung/smdk6400/smdk6400.c
@@ -72,7 +72,6 @@
 	/* Enable WAIT */
 	SROM_BW_REG |= 4 | 8 | 1;
 
-	gd->bd->bi_arch_number = MACH_TYPE;
 	gd->bd->bi_boot_params = PHYS_SDRAM_1 + 0x100;
 
 	return 0;
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