packaging: Simplify OVMF repo clone

Instead of cloning the repo, and then switching to a specific branch,
let's take advantage of `--branch` and directly clone the specific
branch / tag.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

tools/packaging/static-build/ovmf/build-ovmf.sh

@@ -36,9 +36,8 @@ info "Build ${ovmf_repo} version: ${ovmf_version}"
 
 build_root=$(mktemp -d)
 pushd $build_root
-git clone "${ovmf_repo}"
+git clone --single-branch --depth 1 -b "${ovmf_version}" "${ovmf_repo}"
 cd "${ovmf_dir}"
-git checkout "${ovmf_version}"
 git submodule init
 git submodule update