xilinx: board: Update the kaslr-seed property

Create a ft_board_setup() api that gets called as part
of bootm/booti before jumping to kernel. In this
ft_board_setup() callback that will inspect the DTB
and insert the device tree blob with the "kaslr-seed" property.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20240117032014.1014084-2-venkatesh.abbarapu@amd.com