DMDetector: fix nasty x <-> y parameter order bug in DetectPure

This fixes the at least 4 year old bug that popped up in zxing-cpp#773.

The top/left parameters in `Deflate()` should be changed but that could
potentially break client code, so I decided against it.

core/src/datamatrix/DMDetector.cpp

@@ -953,7 +953,7 @@ static DetectorResult DetectPure(const BitMatrix& image)
 	int bottom = top + height - 1;
 
 	// Now just read off the bits (this is a crop + subsample)
-	return {Deflate(image, dimT, dimR, top + modSizeX / 2, left + modSizeY / 2, modSize),
+	return {Deflate(image, dimT, dimR, top + modSizeY / 2, left + modSizeX / 2, modSize),
 			{{left, top}, {right, top}, {right, bottom}, {left, bottom}}};
 }