programs: cmake: Fix relative path warnings

The path to source files were relative which triggered
warnings when generating the build system.

Move to absolute paths based on CMAKE_CURRENT_SOURCE_DIR.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/programs/test/CMakeLists.txt b/programs/test/CMakeLists.txt
index a26c096..ec36d67 100644
--- a/programs/test/CMakeLists.txt
+++ b/programs/test/CMakeLists.txt
@@ -28,7 +28,7 @@
 target_link_libraries(zeroize mbedcrypto)
 
 add_executable(query_compile_time_config query_compile_time_config.c)
-target_sources(query_compile_time_config PUBLIC query_config.c)
+target_sources(query_compile_time_config PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/query_config.c)
 target_link_libraries(query_compile_time_config mbedcrypto)
 
 install(TARGETS selftest benchmark udp_proxy query_compile_time_config