MLECO-3710: Fix for freshly updated submodule build issue.

TensorFlow Lite Micro can have stale third party components downloaded
by an older version. On a submodule update, our recommendation to users
would be to use `-DTENSORFLOW_LITE_MICRO_CLEAN_DOWNLOADS=ON` to clean
the older downloads. Moving the triggered cleaning and refresh to CMake
configuration stage (with no parallel build option). This should have a
better chance of success with the subsequent build step.

Change-Id: I305439c09658f49765ecc15eb1ce0c8b914dd30a
diff --git a/scripts/cmake/tensorflow.cmake b/scripts/cmake/tensorflow.cmake
index d807416..29d5bce 100644
--- a/scripts/cmake/tensorflow.cmake
+++ b/scripts/cmake/tensorflow.cmake
@@ -71,7 +71,16 @@
 endif()
 
 if (TENSORFLOW_LITE_MICRO_CLEAN_DOWNLOADS)
-    list(APPEND MAKE_TARGETS_LIST "clean_downloads")
+    message(STATUS "Refreshing TensorFlow Lite Micro's third party downloads...")
+    execute_process(
+        COMMAND make -f ${TENSORFLOW_LITE_MICRO_PATH}/tools/make/Makefile clean_downloads third_party_downloads
+        RESULT_VARIABLE return_code
+        WORKING_DIRECTORY ${TENSORFLOW_SRC_PATH})
+    if (NOT return_code EQUAL "0")
+        message(FATAL_ERROR "Failed to clean TensorFlow Lite Micro's third party downloads.")
+    else()
+        message(STATUS "Refresh completed.")
+    endif ()
 endif()
 
 if (TENSORFLOW_LITE_MICRO_CLEAN_BUILD)