extmod/modbluetooth: Fix func prototype, empty args should be (void).
extmod/modbluetooth: Fix func prototype, empty args should be (void).

This fixes a -Wstrict-prototypes error.

MrSurly/micropython,tobbad/micropython,adafruit/circuitpython,pozetroninc/micropython,pramasoul/micropython,henriknelson/micropython,pramasoul/micropython,henriknelson/micropython,adafruit/circuitpython,pozetroninc/micropython,henriknelson/micropython,adafruit/circuitpython,MrSurly/micropython,bvernoux/micropython,tobbad/micropython,selste/micropython,pozetroninc/micropython,henriknelson/micropython,pramasoul/micropython,adafruit/circuitpython,bvernoux/micropython,pramasoul/micropython,adafruit/circuitpython,MrSurly/micropython,kerneltask/micropython,tobbad/micropython,tobbad/micropython,tobbad/micropython,MrSurly/micropython,kerneltask/micropython,MrSurly/micropython,pozetroninc/micropython,kerneltask/micropython,kerneltask/micropython,kerneltask/micropython,pozetroninc/micropython,henriknelson/micropython,bvernoux/micropython,pramasoul/micropython,selste/micropython,selste/micropython,bvernoux/micropython,bvernoux/micropython,selste/micropython,adafruit/circuitpython,selste/micropython