AP_GPS_MAV: fix hdop conversion

libraries/AP_GPS/AP_GPS_MAV.cpp

@@ -69,11 +69,11 @@ void AP_GPS_MAV::handle_msg(const mavlink_message_t *msg)
     state.location.options = 0;
 
     if (have_hdop) {
-        state.hdop = packet.hdop * 10; //In centimeters
+        state.hdop = packet.hdop * 100; // convert to centimeters
     }
 
     if (have_vdop) {
-        state.vdop = packet.vdop * 10; //In centimeters
+        state.vdop = packet.vdop * 100; // convert to centimeters
     }
 
     if (have_vel_h) {