Core: Update IPC implementation framework

Initial IPC patches showcases API usage with a rough design. To follow
PSA FF specification, an updated framework needs to take place instead
of previous design.
The modification details are:
- Remove legacy version files which unused anymore: psa_api.c,
  tfm_queue.c, tfm_queue.h, tfm_thread.c and tfm_thread.h.
- Add psa client and service implement on secure side in thread mode.
- Add syscalls for psa client and service, empty now and to be
  implemented.
- Those files in 'core' folder which needed by ipc will be added in
  'ipc' folder. So there is no ipc file to be built in 'library' mode.

Change-Id: I5ab5ea2774dfb70b24f4bfd0499129ae48b2b3de
Signed-off-by: Edison Ai <edison.ai@arm.com>
Co-authored-by: Ken Liu <ken.liu@arm.com>
17 files changed