Add a helper that checks for the fast training capability given the DPCD
receiver capabilities blob.
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021143437.1477719-4-thierry.reding@gmail.com