zynqmp: PSCI: Wait for FW completing wake requests
zynqmp: PSCI: Wait for FW completing wake requests

Powering up cores didn't wait for the PMUFW to complete the request,
which could result in cores failing to power up in Linux.

Reported-by: Koteswararao Nayudu <1b64f0ae3e0e042bab7614e30e5776ec1675824a@xilinx.com>
Signed-off-by: Soren Brinkmann <f9793267bd24439886cd4a142f9642a9bcc6364b@xilinx.com>

lsigithub/arm-trusted-firmware_public,achingupta/arm-trusted-firmware,sbranden/arm-trusted-firmware,lsigithub/arm-trusted-firmware_public,sbranden/arm-trusted-firmware,achingupta/arm-trusted-firmware