Documentation: devicetree: Fix Xilinx VDMA specification

The specification requires xlnx,data-width, but example and driver use
xlnx,datawidth. Change the specification to match the implementation.

Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Fixes: eebeac03db93 ("dma: Add Xilinx Video DMA DT Binding Documentation")
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
doc: dt: vendor-prefixes: Add Digilent Inc

Digilent is a board designer, making various Linux capabable FPGA and
processor boards. Add to the vendor list.

Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
arm: dts: zynq: Move crystal freq. to board level

The fact that all supported boards use the same 33MHz crystal is a
co-incidence. The Zynq PS support a range of crystal freqs so the
hardcoded setting should be removed from the dtsi. Re-implement it
on the board level.

This prepares support for Zynq boards with different crystal
frequencies (e.g. the Digilent ZYBO).

Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
arm: dts: zynq: Add Digilent ZYBO board

Add a DTS describing the Digilent ZYBO board. Similar to ZED but with
a 50MHz crystal instead of 33MHz.

Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>