km: adapt defines and variables for new memory layout

Due to increasing kernel image sizes we get problems when decompressing
the kernel image. To fix this we need to change the addresses where we
load and where we extract the kernel. Also we need to adapt the address
where to load the CRAMFS image and where to load the DTB file.
While at it also harmonize all boards for PPC and ARM to have the
same values. Also we add a new variable "env_version", so that the
userspace is able to detect if this is a u-boot binary with updated
values or not.

CC: Valentin Longchamp <valentin.longchamp@hitachi-powergrids.com>
CC: Heiko Schocher <hs@denx.de>
CC: Tom Rini <trini@konsulko.com>
Signed-off-by: Holger Brunck <holger.brunck@hitachi-powergrids.com>
Reviewed-by: Heiko Schocher <hs@denx.de>