arm64: zynqmp: Move timeout for clock propagation below psu_init

Delay required for clock propagation is tighly coupled with initialization
done in psu_init(). That's why call it also for u-boot proper with
CONFIG_ZYNQMP_PSU_INIT_ENABLED enabled.

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