CBMEM: Backup top_of_ram instead of cbmem_toc

AMD northbridges have a complex way to resolve top_of_ram.
Once it is resolved, it is stored in NVRAM to be used on resume.

TODO: Redesign these get_top_of_ram() functions from scratch.

Change-Id: I3cceb7e9b8b07620dacf138e99f98dc818c65341
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3557
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
15 files changed