SPM: Sort out tfm_secure_api.c file

- Rename 'tfm_utils.h' to 'utilities.h'.
- Rename 'tfm_spm_services_api.h'to 'tfm_spm_services.h'.
- Move 'tfm_secure_api.c' from spm/runtime to spm/model_func and
  sort out the content

Change-Id: Ie8831e2b1430eab6a2edc9b6c0487ef14f2fafc6
Signed-off-by: Summer Qin <summer.qin@arm.com>
42 files changed