fix all sign-compare warnings

src/lib/controllib/BlockLowPassVector.hpp

@@ -66,14 +66,14 @@ public:
 		_state(),
 		_fCut(this, "") // only one parameter, no need to name
 	{
-		for (int i = 0; i < M; i++) {
+		for (size_t i = 0; i < M; i++) {
 			_state(i) = 0.0f / 0.0f;
 		}
 	}
 	virtual ~BlockLowPassVector() {}
 	matrix::Vector<Type, M> update(const matrix::Matrix<Type, M, 1> &input)
 	{
-		for (int i = 0; i < M; i++) {
+		for (size_t i = 0; i < M; i++) {
 			if (!PX4_ISFINITE(getState()(i))) {
 				setState(input);
 			}