Also add new 'invalid' host event bit; if the host reads this, it
knows the memory-mapped data for current events is invalid.
BUG=chrome-os-partner:11146
TEST=manual
On host, ectool eventget -> should print events = 0
On EC, hostevent set 0x80000000
On host, ectool eventget -> should print events = invalid
Reboot EC; should see debug output where event mask 0x2000 is set
during the boot process.
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Change-Id: I8d3f161eec25db50ac06e3642a1a1fb8edb9590e
Reviewed-on: https://gerrit.chromium.org/gerrit/26876
1e8e8cd6aa