util/cbmem: Handle EC_VBOOT_DONE timestamp

util/cbmem: Handle EC_VBOOT_DONE timestamp

This timestamp marks that EC verification has completed.

BUG=chromium:537269
TEST=Run cbmem on glados, verify "1030:finished EC verification" is
seen.
BRANCH=None

Change-Id: I0114febae689584ec8b12c169e70f2d3995d8d4d
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: deeb2ab8085e5ea0a180633eb8fb1c86aadffe94
Original-Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Original-Change-Id: I4f09e970ffedc967c82e6283973cbbcb2fbe037f
Original-Reviewed-on: https://chromium-review.googlesource.com/309280
Original-Commit-Ready: Shawn N <shawnn@chromium.org>
Original-Tested-by: Shawn N <shawnn@chromium.org>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/12230
Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>
Tested-by: build bot (Jenkins)