elog: add extended management engine event
We are seeing ME disabled and ME error events on some devices
and this extended info can help with debug.
Also fix a potential issue where if the log does manage to get
completely full it will never try to shrink it because the only
call to shrink the log happens after a successful event write.
Add a check at elog init time to shrink the log size.
Change-Id: Ib81dc231f6a004b341900374e6c07962cc292031
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1739
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>