And using "-B" means mpy-cross is forcefully rebuilt, sometimes with
invalid CFLAGS_EXTRA options which makes the auto-build fail.
Signed-off-by: Damien George <damien@micropython.org>
The firmware for Teensy 4.0, Teensy 4.1 and MIMXRT1020_EVK are created.
Users of other MIMXRT10xx_EVK boards should be able to build the firmware
themselves, they might need specific DEBUG settings.
The Makefile had to be changed in order to build the .bin file as well.
