Spresense: add CIRCUITPY_BOARD_ID because it doesn't use BASE_CFLAGS
Spresense: add CIRCUITPY_BOARD_ID because it doesn't use BASE_CFLAGS

adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython