mx51evk: Place machine ID into board config

Let common code set the machine ID.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/board/freescale/mx51evk/mx51evk.c b/board/freescale/mx51evk/mx51evk.c
index 94ea1f2..8da1ee8 100644
--- a/board/freescale/mx51evk/mx51evk.c
+++ b/board/freescale/mx51evk/mx51evk.c
@@ -403,7 +403,6 @@
 {
 	system_rev = get_cpu_rev();
 
-	gd->bd->bi_arch_number = MACH_TYPE_MX51_BABBAGE;
 	/* address of boot parameters */
 	gd->bd->bi_boot_params = PHYS_SDRAM_1 + 0x100;
 
diff --git a/include/configs/mx51evk.h b/include/configs/mx51evk.h
index 7d05dc8..d62a4f2 100644
--- a/include/configs/mx51evk.h
+++ b/include/configs/mx51evk.h
@@ -48,6 +48,7 @@
 
 #define CONFIG_OF_LIBFDT		1
 
+#define CONFIG_MACH_TYPE	MACH_TYPE_MX51_BABBAGE
 /*
  * Size of malloc() pool
  */