[TF-M] Interface: Remove unused header include

Hi,

The patchset https://review.trustedfirmware.org/c/trusted-firmware-m/+/3620 removes the header `tfm_veneers.h` from PSA IPC API source files. If there are no objects then can this patchset be merged?

Thanks, Dev IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.