Platform: Reorganize and rename sse_200_mps2 folder

This patch reorganizes and renames sse_200_mps2
folder to be able to add new MPS2 subsystems.
The patch applies the following changes:
- renames sse_200_mps2 to mps2 in order to be
  able to add new MPS2 subsystems
- create the an521 folder to add all SMM-SSE-200
  files. AN521 is the name of Soft Macro
  Model (SMM) SSE-200 subsytem for MPS2
- refactor smm_mps2.h file to make it generic
  across all mps2 subsystems.
- updates cmake files to use the new paths
- removes unnecessary include files in cmake
  setting files
- removes unnecessary files for mps2 and an521

Change-Id: I1ceb1e371fdfb90ac4aa1e3403868a3f01ada2e6
Signed-off-by: Marc Moreno <marc.morenoberengue@arm.com>
diff --git a/bl2/ext/mcuboot/scripts/assemble.py b/bl2/ext/mcuboot/scripts/assemble.py
index 1523964..c2c5d18 100644
--- a/bl2/ext/mcuboot/scripts/assemble.py
+++ b/bl2/ext/mcuboot/scripts/assemble.py
@@ -1,7 +1,7 @@
 #! /usr/bin/env python3
 #
 # Copyright 2017 Linaro Limited
-# Copyright (c) 2017, Arm Limited.
+# Copyright (c) 2017-2018, Arm Limited.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -44,7 +44,7 @@
         sizes = {}
 
         scriptsDir = os.path.dirname(os.path.abspath(__file__))
-        path = '../../../../platform/ext/target/sse_200_mps2/sse_200/partition/flash_layout.h'
+        path = '../../../../platform/ext/target/mps2/an521/partition/flash_layout.h'
         configFile = os.path.join(scriptsDir, path)
 
         with open(configFile, 'r') as fd: