scripts/image_signing/make_dev_ssd.sh: Replace flashrom call

Just use futility directly.

BUG=b:260531154
TEST=```
localhost ~ # futility gbb -g --flash --rootkey=/tmp/rkey >/dev/null 2>&1
localhost ~ # od /tmp/rkey | head -130 | md5sum | sed 's/ .*$//'
a13642246ef93daaf75bd791446fec9b
```

Change-Id: I1aa3b52f568a5e78255b52a15d68258cc9d9aa44
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/4269750
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
Commit-Queue: Yu-Ping Wu <yupingso@chromium.org>
Tested-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Auto-Submit: Edward O'Callaghan <quasisec@chromium.org>
1 file changed