CBMEM: Implement cbmem_run_init_hooks() stub

Until we completely can unify early_variables, use these to
handle CBMEM update hooks for both romstage and ramstage.

For x86, CAR_MIGRATE serves the purpose of romstage hooks.

Change-Id: I100ebc0e35e1b7091b4f287ca37f539fd7c9fa7a
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/7876
Reviewed-by: Aaron Durbin <adurbin@google.com>
Tested-by: build bot (Jenkins)
9 files changed