message: updated micro_speech readme.md
diff: @@ -267,7 +267,7 @@ The following command will download the required dependencies and then compile a
  binary for the SparkFun Edge:
  ```
  -make -f tensorflow/lite/micro/tools/make/Makefile TARGET=sparkfun_edge TAGS="cmsis_nn" micro_speech_bin
  +make -f tensorflow/lite/micro/tools/make/Makefile TARGET=sparkfun_edge OPTIMIZED_KERNEL_DIR=cmsis_nn micro_speech_bin
  ```
  The binary will be created in the following location:
  