firmware: Add a type to LCOV tarball info

The LCOV tarball info has to have at least one field so that we can
identify the type.

BUG=b:156895937
TEST=generate

Change-Id: Idfa91fb781833e0b53a22dc8fefdb618a125d1d2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2770979
Reviewed-by: LaMont Jones <lamontjones@chromium.org>
Commit-Queue: Paul Fagerburg <pfagerburg@chromium.org>
2 files changed