arm: xlnx-zynqmp: Add xlnx-dp and xlnx-dpdma

This adds the DP and the DPDMA to the Zynq MP platform.

Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Tested-By: Hyun Kwon <hyun.kwon@xilinx.com>
Message-id: 1465833014-21982-10-git-send-email-fred.konrad@greensocs.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>