Add CX9020 board based on mx53loco.
Add simplified imx53 base device tree from kernel v4.8-rc8, to reuse
serial_mxc with DTE and prepare for device tree migration of other
functions and imx53 devices.

The CX9020 differs from i.MX53 Quick Start Board by:
- use uart2 instead of uart1
- DVI-D connector instead of VGA
- no audio
- CCAT FPGA connected to emi
- enable rtc
Signed-off-by: NPatrick Bruenn <p.bruenn@beckhoff.com>

Add PL bitstream dowload support for ZynqMP
Bitstream will be validated by uboot and loaded
to PL by invoking an smc instruction to ATF which route this request to
PMU FW which will take care of loading it to PL
Signed-off-by: NSiva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

Add missing Kconfig to fpga subsystem to be able
to add new options.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>