nrf: Remove old qstr defines
nrf: Remove old qstr defines

These were used by the microbit music module, which was removed.

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