Convert to yaml the VersaClock bindings document. The mapping between clock specifier and physical pins cannot be described formally in yaml schema, then keep it verbatim in the description field. Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net> Link: https://lore.kernel.org/r/20200723074112.3159-4-luca@lucaceresoli.net Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Stephen Boyd <sboyd@kernel.org>