nrf: Fix missing LED GPIO initialization
nrf: Fix missing LED GPIO initialization

led_init was never called, which means the GPIOs were never set to
output and the LEDs didn't work.

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