crossystem: Add fw_prev_tried and fw_prev_result to output values

CL:221230 added the new NVRAM fields fw_prev_tried and fw_prev_result.
It also provided support in the crossystem library to decode these
values, but it forgot to add them to the table of allowed crossystem
options so they actually cannot be queried by the command line tool. Fix
that since this information is useful to debug failures after updating.

BRANCH=R41
BUG=chrome-os-partner:36183
TEST=make runtests VBOOT2=1. cros deployed onto Jerry and confirmed
fw_prev_tried and fw_prev_result are correct.

Change-Id: I8bad7266379d959f5370b7ebeefbbba939c5de06
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/245143
Reviewed-by: Randall Spangler <rspangler@chromium.org>
(cherry picked from commit 65ce99b3e2c75bbb416b6edf78b5ea0d7f8c3a94)
Reviewed-on: https://chromium-review.googlesource.com/245860
1 file changed