Test: Remove app header from test folder

Test should not include app header files. 'execute_ns_interactive_tests'
is only used in 'core_ns_interactive_testsuite.c', so remove the
declaration in 'app/tfm_integ_test.h' and change the function attribute
to 'static'. Thus, test doesn't need to include app header files.

Change-Id: I9cb2c3dd3eba2d718b998be85619235f2515481c
Signed-off-by: Summer Qin <summer.qin@arm.com>
diff --git a/app/tfm_integ_test.h b/app/tfm_integ_test.h
index 778f2ae..93c46a5 100644
--- a/app/tfm_integ_test.h
+++ b/app/tfm_integ_test.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2017-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -35,12 +35,6 @@
 void test_app(void *argument);
 #endif /* TEST_FRAMEWORK_NS */
 
-/**
- * \brief Execute the interactive test cases (button push)
- *
- */
-void execute_ns_interactive_tests(void);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/test/suites/core/non_secure/core_ns_interactive_testsuite.c b/test/suites/core/non_secure/core_ns_interactive_testsuite.c
index 36cd2d1..a9464ee 100644
--- a/test/suites/core/non_secure/core_ns_interactive_testsuite.c
+++ b/test/suites/core/non_secure/core_ns_interactive_testsuite.c
@@ -7,7 +7,6 @@
 
 #include "core_ns_tests.h"
 #include "tfm_api.h"
-#include "app/tfm_integ_test.h"
 #include "cmsis_os2.h"
 #include "tfm_nspm_api.h"
 #include "tfm_veneers.h"
@@ -63,7 +62,7 @@
                   core_tests, list_size, p_test_suite);
 }
 
-void execute_ns_interactive_tests(void);
+static void execute_ns_interactive_tests(void);
 
 /**
  * \brief Tests core function with interactive test cases
@@ -416,7 +415,7 @@
  * \brief Execute the interactive tets cases
  *
  */
-void execute_ns_interactive_tests(void)
+static void execute_ns_interactive_tests(void)
 {
     uint8_t idx;