zynq_common: Change the default server and ip address

Changed the default server and ip address w.r.t systest control
pc as systest is a default environment to run.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
zynq_common: Enable bootz command

bootz command add option to enable booting zImages.

Booting commands with external dtb:
tftp 0x8000 zImage
tftp 0x2A00000 devicetree.dtb
tftp 0x2000000 uramdisk.image.gz
bootz 0x8000 0x2000000 0x2A00000

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
zynq: Support fpga command for all zynq families

Detect zynq idcode and based on that setup fpga device
which is connected to it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>