extmod/moductypes: Remove BITFIELD from aggregate types enum.
extmod/moductypes: Remove BITFIELD from aggregate types enum.

This value is unused. It was an artifact of early draft design, but
bitfields were optimized to use scalar one-word encoding, to allow
compact encoding of typical multiple bitfields in MCU control
registers.

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