AP_NavEKF2: use vector comparison for new mag vector

libraries/AP_NavEKF2/AP_NavEKF2_Measurements.cpp

@@ -185,7 +185,7 @@ void NavEKF2_core::readMagData()
 
         // detect changes to magnetometer offset parameters and reset states
         Vector3f nowMagOffsets = _ahrs->get_compass()->get_offsets(magSelectIndex);
-        bool changeDetected = lastMagOffsetsValid && (!is_equal(nowMagOffsets.x,lastMagOffsets.x) || !is_equal(nowMagOffsets.y,lastMagOffsets.y) || !is_equal(nowMagOffsets.z,lastMagOffsets.z));
+        bool changeDetected = lastMagOffsetsValid && (nowMagOffsets != lastMagOffsets);
         if (changeDetected) {
             // zero the learned magnetometer bias states
             stateStruct.body_magfield.zero();