ARM64: zynqmp: Fix W=1 dtc 1.4 warnings

The patch removes these warnings reported by dtc 1.4:
Warning (unit_address_vs_reg): Node /amba_apu has a reg or ranges
property, but no unit name
Warning (unit_address_vs_reg): Node /memory has a reg or ranges
property, but no unit name

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