arm64: zynqmp: Add idcode for new RFSoC silicon ZU39DR

This patch adds "zu39dr" to the list of zynqmp devices
The zu39DR is the new RFSoC silicon with id value of 0x66.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>