Add a DTS describing the Digilent ZYBO board. Similar to ZED but with
a 50MHz crystal instead of 33MHz.
Acked-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NPeter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>