arm64: zynqmp: Add psgtr description to zc1751 dc1 board

Wire psgtr for zc1751 dc1 board.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/51d9a5e0aa26b0ea79b8823bf3d15f4e2542f927.1623684253.git.michal.simek@xilinx.com