test_interfaces.c: fixed a compilation error

tests/datawizard/interfaces/test_interfaces.c

@@ -135,6 +135,7 @@ data_interface_test_summary_success(data_interface_test_summary *s)
 }
 
 enum operation {
+	CPU_TO_CPU,
 #ifdef STARPU_USE_CUDA
 	CPU_TO_CUDA,
 	CUDA_TO_CUDA,