ARM: Reintroduce MACH_TYPE_KM_KIRKWOOD for keymile ARM boards

We got dropped from Linux mach-types.h because of a lack of mainline
support and this is needed since the last Linux/u-boot mach-types
synchro.

This patch also defines CONFIG_MACH_TYPE for all keymile boards, as
this is a mandatory CONFIG for ARM boards now. The initialization
of gd->bd->bi_arch_number is removed form km_arm.c, our board file.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>
diff --git a/include/configs/km/km_arm.h b/include/configs/km/km_arm.h
index c117943..f30088d 100644
--- a/include/configs/km/km_arm.h
+++ b/include/configs/km/km_arm.h
@@ -36,6 +36,9 @@
 #ifndef _CONFIG_KM_ARM_H
 #define _CONFIG_KM_ARM_H
 
+/* We got removed from Linux mach-types.h */
+#define MACH_TYPE_KM_KIRKWOOD          2255
+
 /*
  * High Level Configuration Options (easy to change)
  */
@@ -45,6 +48,8 @@
 #define CONFIG_KW88F6281		/* SOC Name */
 #define CONFIG_MACH_KM_KIRKWOOD		/* Machine type */
 
+#define CONFIG_MACH_TYPE	MACH_TYPE_KM_KIRKWOOD
+
 /* include common defines/options for all Keymile boards */
 #include "keymile-common.h"