This only adds support in the EC; it doesn't add an ectool command.
We'll add that later. This also fixes a bug where the reserved byte
in the panic data structure wasn't being set to 0.
BUG=chrome-os-partner:7466
BRANCH=all
TEST=manual
1. crash unaligned -> system crashes
2. hostcmd 0xd3 -> returns a hex string 01010100...506e6321
3. hostcmd 0xd3 -> returns a hex string 01010500...506e6321
Change-Id: I1de8e19c44c835055d893986b42d152dc704c35f
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/32183
Reviewed-by: Simon Glass <sjg@chromium.org>