km/common: simplify debug environment

The debug environment which is stored in textfiles in the
scripts directory was reworked. Two usecase are now present
which can be executed simply from the default environment:
run develop: this configures the environment to setup the
             rootfs via nfs
run ramfs: this configures the environment to setup the
           rootfs in ram

Each architecture now has a "arch" variable which is used
to load the architecture specific debug scripts and to set
the rootpath for NFS.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
diff --git a/include/configs/km/km8321-common.h b/include/configs/km/km8321-common.h
index 6fab45e..902ae26 100644
--- a/include/configs/km/km8321-common.h
+++ b/include/configs/km/km8321-common.h
@@ -33,8 +33,7 @@
 #define CONFIG_MPC832x	/* MPC832x CPU specific */
 #define CONFIG_KM8321	/* Keymile PBEC8321 board specific */
 
-#define CONFIG_KM_DEF_ROOTPATH		\
-	"rootpath=/opt/eldk/ppc_8xx\0"
+#define CONFIG_KM_DEF_ARCH	"arch=ppc_8xx\0"
 
 /* include common defines/options for all 83xx Keymile boards */
 #include "km83xx-common.h"