arm64: zynqmp: Disable CCI by default

There is no reason to have CCI no enabled by default. Enable it when your
system configuration requires it. In Xilinx configuration flow this is work
for Device Tree Generator which reads information from HW Design
configuration.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/f507d45fbaa0bd31f641e758efa40a2532466ced.1623684253.git.michal.simek@xilinx.com