Error caused by repeated code

[dugushiyu]

MadgwickAHRS/src/MadgwickAHRS.cpp

Lines 237 to 238 in 7b6a635

	y = y * (1.5f - (halfx * y * y));
	y = y * (1.5f - (halfx * y * y));

error................................

[izu-co]

It's a little late, but if you look at the referenced Wikipedia article, you can see that a second iteration is indeed possible.