Document what this job cover (build X86 targets with
KVM being the single accelerator available).

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201207131503.3858889-2-philmd@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>