AP_GPS_UBlox: remove unused member

libraries/AP_GPS/AP_GPS_UBLOX.cpp

@@ -67,8 +67,7 @@ AP_GPS_UBLOX::AP_GPS_UBLOX(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UART
     _disable_counter(0),
     next_fix(AP_GPS::NO_FIX),
     rate_update_step(0),
-    _last_5hz_time(0),
-    _last_hw_status(0)
+    _last_5hz_time(0)
 {
     // stop any config strings that are pending
     gps.send_blob_start(state.instance, NULL, 0);

libraries/AP_GPS/AP_GPS_UBLOX.h

@@ -358,7 +358,6 @@ private:
 
     uint8_t rate_update_step;
     uint32_t _last_5hz_time;
-    uint32_t _last_hw_status;
 
     void 	    _configure_navigation_rate(uint16_t rate_ms);
     void        _configure_message_rate(uint8_t msg_class, uint8_t msg_id, uint8_t rate);