Set up an arbitrary amount of system memory on Geode LX, so

Set up an arbitrary amount of system memory on Geode LX, so
coreboot_ram can be unpacked to 1MB. The value is quickly
replaced with the real value later, thus causing no harm.

Move RAMBASE to the default of 1MB for the affected boards

Signed-off-by: Aurelien Guillaume <aurelien@iwi.me>
Acked-by: Patrick Georgi <patrick.georgi@coresystems.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5779 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1