elog: use platform's region attributes to find elog

** Cherry-picked from the master branch. **

This uses the platform's pre-defined region attributes to find
the region using the fmap. The advantage to this approach is that
the eventlog region's name can be specified on a per-platform basis.

BUG=chrome-os-partner:16132
BRANCH=spring
TEST=Used to read the event log on spring with other dependent changes.

Change-Id: I810d5e4e14634cfb140f37849997ed4b4f34ddcb
Reviewed-on: https://gerrit.chromium.org/gerrit/50023
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/58519
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
1 file changed