mambo: Increase memory to 4GB and change memory map
mambo: Increase memory to 4GB and change memory map

Increase memory in the sim to 4GB up from 1GB.  We need to turn off
the small RAM and ROM in mambo as that sits at 3.75GB currently.  We
don't use these currently.

Also change where we put the CPIO to give ourselves more space.

Signed-off-by: Michael Neuling <7b0ab45a730e48a69239010b5b8fe5fa4e8eaac6@neuling.org>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

open-power/skiboot,open-power/skiboot,shenki/skiboot,stewart-ibm/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,legoater/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,mikey/skiboot,qemu/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot,qemu/skiboot,stewart-ibm/skiboot,open-power/skiboot,mikey/skiboot,mikey/skiboot,shenki/skiboot,open-power/skiboot,qemu/skiboot,qemu/skiboot,stewart-ibm/skiboot