Merge pull request #6889 from thinkyhead/bf_at90usb_mapping

Marlin/Marlin_main.cpp

Marlin/boards.h

Marlin/fastio.h

Marlin/fastio_AT90USB-Marlin.h

Marlin/fastio_AT90USB.h

Marlin/pins.h

Marlin/pinsDebug.h

Marlin/pinsDebug_Teensyduino.h

Marlin/pinsDebug_list.h

Marlin/pins_5DPRINT.h

Marlin/pins_AZTEEG_X3_PRO.h

Marlin/pins_BRAINWAVE.h

Marlin/pins_BRAINWAVE_PRO.h

Marlin/pins_GEN6.h

Marlin/pins_GEN7_CUSTOM.h

Marlin/pins_MEGATRONICS_3.h

Marlin/pins_MIGHTYBOARD_REVE.h

Marlin/pins_MINITRONICS.h

Marlin/pins_PRINTRBOARD.h

Marlin/pins_PRINTRBOARD_REVF.h