attitude_estimator_q: don't spam console

We should not spam the console just because the input data is
degenerate, it would only make things worse because everything would
slow down due to the printfs.

src/modules/attitude_estimator_q/attitude_estimator_q_main.cpp

@@ -355,7 +355,7 @@ void AttitudeEstimatorQ::task_main()
 				_accel(2) = _lp_accel_z.apply(sensors.accelerometer_m_s2[2]);
 
 				if (_accel.length() < 0.01f) {
-					warnx("WARNING: degenerate accel!");
+					PX4_DEBUG("WARNING: degenerate accel!");
 					continue;
 				}
 			}
@@ -366,7 +366,7 @@ void AttitudeEstimatorQ::task_main()
 				_mag(2) = sensors.magnetometer_ga[2];
 
 				if (_mag.length() < 0.01f) {
-					warnx("WARNING: degenerate mag!");
+					PX4_DEBUG("WARNING: degenerate mag!");
 					continue;
 				}
 			}