arm: zynq: Add support for Bitmain Antminer S9 control board

arm: zynq: Add support for Bitmain Antminer S9 control board

This is control board on Bitmain Antminer S9.
There are 3 board variables with 256MB, 512MB and 1024MB DDR.
DDR memory is automatically detected with using get_with using
get_ram_size().

Bitmain is using 16MB space for FPGA which is handled via
reserved-memory. Also U-Boot is allocating 16B for storing bootcounts.
Watchdog is started but never service in U-Boot.

SPL MMC is working. SPL NAND is not working because it is not supported
as of now.

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>