Replace the free-form description of device tree bindings for VSC9959Reviewed-by: Maxim Kochetkov <fido_max@xxxxxxxx>
and VSC9953 with a YAML formatted dt-schema description. This contains
more or less the same information, but reworded to be a bit more
succint.
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>