Fix inverted forward, backward, left and right motor controls

[matr1xp]

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[MallocArray]

I agree that it typically seems to need this inversion, but I've had a few kits that didn't need it, or we did invert it and then later we had to remove the inversion.
It is mentioned in the Tutorial.pdf that you may need to add this line. if it defaulted to inverted, then the PDF would need to be updated to say it may need to remove the - before -duty.

May be best to leave it as is and the instructions to invert as needed.