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/platform/ext/psoc64.cmake b/platform/ext/psoc64.cmake
index b985001..bcf7824 100644
--- a/platform/ext/psoc64.cmake
+++ b/platform/ext/psoc64.cmake
@@ -225,9 +225,9 @@
 elseif(BUILD_TARGET_NV_COUNTERS)
   list(APPEND ALL_SRC_C_S "${PLATFORM_DIR}/target/cypress/psoc64/nv_counters.c")
   set(TARGET_NV_COUNTERS_ENABLE ON)
-  # Sets SST_ROLLBACK_PROTECTION flag to compile in the SST services
+  # Sets PS_ROLLBACK_PROTECTION flag to compile in the PS services
   # rollback protection code as the target supports nv counters.
-  set (SST_ROLLBACK_PROTECTION ON)
+  set (PS_ROLLBACK_PROTECTION ON)
 endif()
 
 if (NOT DEFINED BUILD_CMSIS_DRIVERS)
@@ -245,10 +245,10 @@
   message(FATAL_ERROR "Configuration variable BUILD_FLASH (true|false) is undefined!")
 elseif(BUILD_FLASH)
   list(APPEND ALL_SRC_C "${PLATFORM_DIR}/target/cypress/psoc64/CMSIS_Driver/Driver_Flash.c")
-  # As the SST area is going to be in RAM, it is required to set SST_CREATE_FLASH_LAYOUT
-  # to be sure the SST service knows that when it starts the SST area does not contain any
-  # valid SST flash layout and it needs to create one.
-  set(SST_CREATE_FLASH_LAYOUT ON)
+  # As the PS area is going to be in RAM, it is required to set PS_CREATE_FLASH_LAYOUT
+  # to be sure the PS service knows that when it starts the PS area does not contain any
+  # valid PS flash layout and it needs to create one.
+  set(PS_CREATE_FLASH_LAYOUT ON)
   set(ITS_CREATE_FLASH_LAYOUT ON)
   embedded_include_directories(PATH "${PLATFORM_DIR}/target/cypress/psoc64/CMSIS_Driver" ABSOLUTE)
   embedded_include_directories(PATH "${PLATFORM_DIR}/driver" ABSOLUTE)