vboot: Remove 'streaming_lba_count' field in disk info After removing support for external GPT separate field for LBA count is no longer necessary. BRANCH=none BUG=b:514271116 TEST=make runtests Change-Id: If7500d1477b0e3b7001d6f8a711961c96ca26b6b Signed-off-by: Grzegorz Bernacki <bernacki@google.com> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/7806907 Reviewed-by: Julius Werner <jwerner@chromium.org>