Erasing the flash can take a while, by which time the host may have timed
out. So pass an in-progress message back to the host before starting, and
when done, stash the result for later collection.
BUG=chrome-os-partner:12685
BRANCH=snow,link
TEST=manual
build and boot to kernel on snow
Change-Id: I5566a5519a1c8b320573b20e1ea7660217b32a5e
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/30471