GPS_UBLOX: fix test to work with AP_HAL_Linux.

Some libraries were missing.

libraries/AP_GPS/examples/GPS_UBLOX_passthrough/GPS_UBLOX_passthrough.pde

@@ -14,6 +14,7 @@
 #include <AP_HAL_AVR.h>
 #include <AP_HAL_Empty.h>
 #include <AP_HAL_PX4.h>
+#include <AP_HAL_Linux.h>
 #include <AP_GPS.h>
 #include <DataFlash.h>
 #include <AP_InertialSensor.h>
@@ -30,6 +31,7 @@
 #include <AP_Mission.h>
 #include <AP_Math.h>
 #include <AP_Notify.h>
+#include <AP_NavEKF.h>
 
 const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;