jammy-amd64-tf-a-build-lts2.8: Install "clang" Ubuntu package

This package was removed from mainline image's Dockerfile (it downloads
standalone tarball for newer Clang version instead). But for LTS image,
we still need it.

Similar to change applied to jammy-amd64-tf-a-build-lts2.10.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Ie4b80fb72c63d67e98390e18123d90d66b964eb8
1 file changed