[Tf-a-tests] Invalid entry point in cpu hotplug

Hi Tf-a-tests team,

We have a query regarding TF-A test especially hot-plug request on a CPU with invalid entry-point address, where zero is passed as invalid address. Could you please let us know why address 0x0 is invalid address here ? Please refer to below code path for reference.

https://review.trustedfirmware.org/plugins/gitiles/TF-A/tf-a-tests/+/refs/he...

Regards, Maheedhar.