Tests Reg: Install config_ns_test.cmake to "config" folder

Change-Id: I35e9df25dcad10175f5e1ce06a1ff6133b7be600
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/tests_reg/CMakeLists.txt b/tests_reg/CMakeLists.txt
index 330566a..0833e8c 100644
--- a/tests_reg/CMakeLists.txt
+++ b/tests_reg/CMakeLists.txt
@@ -41,7 +41,7 @@
 
 # If config_ns_test.cmake is exported from TF-M build, it indicates regression tests are enabled.
 # Otherwise, skip test configuration
-include(${CONFIG_SPE_PATH}/config_ns_test.cmake OPTIONAL)
+include(${CONFIG_SPE_PATH}/config/config_ns_test.cmake OPTIONAL)
 if(TFM_NS_REG_TEST)
     # Include platform specific regression tests config
     include(${CONFIG_SPE_PATH}/platform/tests/tfm_tests_config.cmake OPTIONAL)