Workaround for https://github.com/tensorflow/tflite-micro/issues/199.

Change-Id: I35c8179a40b89e78d144813309b7b0e0d8a68285
diff --git a/tflite_micro.cmake b/tflite_micro.cmake
index 2cdc4eb..76609c9 100644
--- a/tflite_micro.cmake
+++ b/tflite_micro.cmake
@@ -60,6 +60,7 @@
 
     # Command and target
     add_custom_target(tflu_gen ALL
+                  COMMAND make -f ${TFLU_PATH}/tools/make/Makefile third_party_downloads
                   COMMAND make -j${J} -f ${TFLU_PATH}/tools/make/Makefile microlite
                           TARGET_TOOLCHAIN_ROOT=${TFLU_TARGET_TOOLCHAIN_ROOT}
                           TOOLCHAIN=${TFLU_TOOLCHAIN}