Build: Add regression test suites out-of-tree build support

This commit support vendors to run platform-specific extra tests with
TF-M regression tests. Tf-m-tests provide a flexible interface to
integrate platform-specific tests. The platform-specific extra tests
can be included via out-of-tree build with tf-m-tests. The
out-of-tree build of extra tests can enable developers to perform
tests quickly and flexibly during development.

Signed-off-by: Jianliang Shen <jianliang.shen@arm.com>
Change-Id: Icd2a6ccc0e26acea36742b39abd72e93ab2399e2
diff --git a/test/framework/non_secure_suites.c b/test/framework/non_secure_suites.c
index f75c768..8424d91 100644
--- a/test/framework/non_secure_suites.c
+++ b/test/framework/non_secure_suites.c
@@ -53,6 +53,9 @@
 #if defined(TEST_NS_SLIH_IRQ) || defined(TEST_NS_FLIH_IRQ)
 #include "irq_testsuite.h"
 #endif
+#ifdef EXTRA_NS_TEST_SUITE
+#include "extra_ns_tests.h"
+#endif
 
 static struct test_suite_t test_suites[] = {
     /* List test cases which are compliant with level 1 isolation */
@@ -116,6 +119,11 @@
     {&register_testsuite_multi_core_ns_interface, 0, 0, 0},
 #endif
 
+#ifdef EXTRA_NS_TEST_SUITE
+    /* Non-secure extra test cases */
+    {&register_testsuite_extra_ns_interface, 0, 0, 0},
+#endif
+
 #ifdef TFM_FUZZER_TOOL_TESTS
     {&register_testsuite_tf_fuzz_test, 0, 0, 0},
 #endif /* TFM_FUZZER_TOOL_TESTS */