Build: Add some missing files in NS build

Install multi-core header files into a dedicated folder.
Install platform common include and crypto key header files.

Change-Id: Ifd6314ddd59205c0e3fc3ae07aaad4205e1f542b
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/cmake/install.cmake b/cmake/install.cmake
index 56951f2..9212877 100644
--- a/cmake/install.cmake
+++ b/cmake/install.cmake
@@ -49,7 +49,7 @@
                         ${INTERFACE_INC_DIR}/multi_core/tfm_mailbox.h
                         ${INTERFACE_INC_DIR}/multi_core/tfm_ns_mailbox_test.h
                         ${CMAKE_BINARY_DIR}/generated/interface/include/tfm_mailbox_config.h
-            DESTINATION ${INSTALL_INTERFACE_INC_DIR})
+            DESTINATION ${INSTALL_INTERFACE_INC_DIR}/multi_core)
 endif()
 
 if (TFM_PARTITION_PROTECTED_STORAGE)
@@ -202,6 +202,9 @@
 install(DIRECTORY ${PLATFORM_DIR}/ext/cmsis
         DESTINATION ${INSTALL_PLATFORM_NS_DIR})
 
+install(DIRECTORY   ${PLATFORM_DIR}/include
+        DESTINATION ${INSTALL_PLATFORM_NS_DIR})
+
 install(FILES ${CMAKE_SOURCE_DIR}/cmake/spe-CMakeLists.cmake
         DESTINATION ${CMAKE_INSTALL_PREFIX}
         RENAME CMakeLists.txt)