vboot: use Fatal instead of VbExError in cmd_vbutil_kernel

BUG=b:124141368
TEST=make clean && make runtests
BRANCH=none

Change-Id: Iff20dcc3aa47bfa29776609e5b352ea464c18241
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1680189
Tested-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed