Build: Enable linking with PSA API compliance tests in the NS app

This change modifies the build system to support linking
the PSA API compliance test static libraries. It introduces
a new build configuration ConfigPsaApiTest.cmake for this purpose.
The build instructions are updated to show an example of how
to use this new build configuration.

Change-Id: Iabf4876504e690826fe80b467a91fa53bffb0b47
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
Co-Authored-by: Antonio de Angelis <antonio.deangelis@arm.com>
diff --git a/ConfigRegression.cmake b/ConfigRegression.cmake
index 14b428d..ad1d583 100755
--- a/ConfigRegression.cmake
+++ b/ConfigRegression.cmake
@@ -1,5 +1,5 @@
 #-------------------------------------------------------------------------------
-# Copyright (c) 2017-2018, Arm Limited. All rights reserved.
+# Copyright (c) 2017-2019, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -28,6 +28,7 @@
 #definitions) based on these.
 set (REGRESSION True)
 set (CORE_TEST False)
+set (PSA_API_TEST False)
 
 # TF-M isolation level: 1..3
 set (TFM_LVL 1)