multirotor mixer: use correct version of delete operator for array pointer

Signed-off-by: Roman <bapstroman@gmail.com>

src/modules/systemlib/mixer/mixer_multirotor.cpp

@@ -102,7 +102,7 @@ MultirotorMixer::MultirotorMixer(ControlCallback control_cb,
 MultirotorMixer::~MultirotorMixer()
 {
 	if (_outputs_prev != nullptr) {
-		delete _outputs_prev;
+		delete[] _outputs_prev;
 	}
 }