km/common: add toolchain variable

Add a variable "toolchain" and configure the rootpath
for the nfsargs with this variable.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
cc: Wolfgang Denk <wd@denx.de>
diff --git a/board/keymile/scripts/README b/board/keymile/scripts/README
index 7fbcf74..dd935b2 100644
--- a/board/keymile/scripts/README
+++ b/board/keymile/scripts/README
@@ -7,7 +7,7 @@
 run develop : setup environment to configure for rootfs via nfs
 run ramfs   : setup environment to configure for rootfs in ram
 
-Last change: 20.05.2011
+Last change: 24.11.2011
 
 develop-common.txt
 ============================