In order to not expose the cbmem data structures to userland
that are used by coreboot internally add each of the cbmem
entries to a coreboot table record. The payload ABI uses
coreboot tables so this just provides a shortcut for cbmem
entries which were manually added previously by doing the
work on behalf of all entries.

A cursor structure and associated functions are added to
the imd code for walking the entries in order to be placed
in the coreboot tables.  Additionally a struct lb_cbmem_entry
is added that lists the base address, size, and id of the
cbmem entry.

BUG=chrome-os-partner:43731
BRANCH=None
TEST=Booted glados. View coreboot table entries with cbmem.

Change-Id: I125940aa1898c3e99077ead0660eff8aa905b13b
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11757


Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)