Build: Align with tf-m-tests app build change

Specify tfm_api_ns/platform_ns target sources and includes.
Only add common files and files exported by TF-M secure build.
Leave others to NS builds.

Other minor changes to align with tf-m-tests app_broker build change.

Change-Id: I50056339494f626d22e000af0407055273fc4ad5
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/interface/CMakeLists.txt b/interface/CMakeLists.txt
index 8dfdd73..3421566 100644
--- a/interface/CMakeLists.txt
+++ b/interface/CMakeLists.txt
@@ -40,6 +40,7 @@
         $<$<BOOL:${CONFIG_TFM_USE_TRUSTZONE}>:CONFIG_TFM_USE_TRUSTZONE>
         $<$<BOOL:${TFM_MULTI_CORE_TOPOLOGY}>:TFM_MULTI_CORE_TOPOLOGY>
         $<$<BOOL:${CONFIG_TFM_PARTITION_META}>:CONFIG_TFM_PARTITION_META>
+        $<$<BOOL:${TEST_NS_MULTI_CORE}>:TFM_MULTI_CORE_TEST>
 )
 
 ###################### PSA api (S lib) #########################################