xilinx: Align dfu ram with booti command

Image should be loaded to 0x80000 address and not to $kernel_addr_r.
Also kernel_addr, fdt_addr and fdt_size in zynqmp case are not defined
that's why define it to be aligned with Versal.

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