cpu/intel/car/core2: Prepare for POSTCAR_STAGE support

Split of the model_6ex cache as ram to support POSTCAR_STAGE, which is
also needed for future C_ENVIRONMENT_BOOTBLOCK.

When using POSTCAR_STAGE the p4-netburst/exit_car.S is using since it
is identical.

Change-Id: Ibe9f065fdf1d702b73333ea7bb32daca15ba1293
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/26783
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
4 files changed