message: more cleanup
  CMSIS_ext is not used in Apollo3 implementation
diff: @@ -91,7 +91,6 @@ $(MAKEFILE_DIR)/downloads/$(AM_SDK_DEST)/$(SF_BSPS_DEST): $(MAKEFILE_DIR)/downlo
  INCLUDES += \
  -isystem$(MAKEFILE_DIR)/downloads/cmsis/CMSIS/Core/Include/ \
  -isystem$(MAKEFILE_DIR)/downloads/cmsis/CMSIS/DSP/Include/ \
  - -I$(MAKEFILE_DIR)/downloads/CMSIS_ext/ \
  -I$(GCC_ARM)/arm-none-eabi/ \
  -I$(APOLLO3_SDK)/mcu/apollo3/ \
  -I$(APOLLO3_SDK)/CMSIS/AmbiqMicro/Include/ \
  