CMake greentea: fix list dir for app.cmake inclusion

Author: 0xc0170

tools/cmake/mbed_greentea.cmake

@@ -3,7 +3,7 @@
 
 set(MBED_CONFIG_PATH ${CMAKE_CURRENT_BINARY_DIR} CACHE INTERNAL "")
 
-include(${mbed-os_SOURCE_DIR}/tools/cmake/app.cmake)
+include(${CMAKE_CURRENT_LIST_DIR}/app.cmake)
 
 # CMake Macro for generalizing CMake configuration across the greentea test suite with configurable parameters
 # Macro args:
@@ -37,7 +37,7 @@ macro(mbed_greentea_add_test)
 
     set(TEST_NAME ${MBED_GREENTEA_TEST_NAME})
 
-    add_subdirectory(${mbed-os_SOURCE_DIR} build)
+    add_subdirectory(${CMAKE_CURRENT_LIST_DIR} build)
 
     add_executable(${TEST_NAME})