SST: Rename SST(Secure STorage) to PS(Protected Storage)

This patches renames SST(Secure STorage) to
PS(Protected Storage) for files, folders and any contents
in files to align with the PSA Storage API spec.

Change-Id: Icf991f59512875780c159f22737b521b3b2d4924
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/docs/user_guides/tfm_integration_guide.rst b/docs/user_guides/tfm_integration_guide.rst
index d320a0e..09e43a0 100644
--- a/docs/user_guides/tfm_integration_guide.rst
+++ b/docs/user_guides/tfm_integration_guide.rst
@@ -67,7 +67,7 @@
 
 .. Note::
 
-    Currently SST and BL2 bootloader use different flash interface
+    Currently ITS, PS and BL2 bootloader use different flash interface
 
 Target configuration files
 ==========================
@@ -104,13 +104,13 @@
 ``<build_dir>/install/export/tfm`` path. The NS side is only allowed to call
 TF-M secure functions (veneers) from the NS Thread mode. For this reason, the
 API is a collection of functions in the ``<build_dir>/install/export/tfm/inc``
-directory. For example, the interface for the Secure STorage (SST) service
-is described in the file ``psa_sst_api.h`` as a collection of functions that
+directory. For example, the interface for the Protected Storage (PS) service
+is described in the file ``psa_ps_api.h`` as a collection of functions that
 call service veneer functions. This API is a wrapper for the secure veneers,
 and returns the return value from the service to the caller.
 
-The secure storage service uses a numerical ID, to identify the clients that use
-the service. For details see
+The protected storage service uses a numerical ID, to identify the clients that
+use the service. For details see
 :doc:`ns client identification documentation <tfm_ns_client_identification>`.
 
 Interface with non-secure world regression tests
@@ -123,7 +123,7 @@
 tests are precompiled and delivered as a static library which is available in
 ``<build_dir>/install/export/tfm/test/lib``, so that the non-secure application
 needs to link against the library to be able to invoke the
-``tfm_non_secure_client_run_tests()`` function. The SST non-secure side
+``tfm_non_secure_client_run_tests()`` function. The PS non-secure side
 regression tests rely on some OS functionality e.g. threads, mutexes etc. These
 functions comply with CMSIS RTOS2 standard and have been exported as thin
 wrappers defined in ``os_wrapper.h`` contained in
@@ -148,4 +148,4 @@
 
 --------------
 
-*Copyright (c) 2017-2019, Arm Limited. All rights reserved.*
+*Copyright (c) 2017-2020, Arm Limited. All rights reserved.*