AP_GPS: adjust for Location_Class and Location unification

libraries/AP_GPS/AP_GPS.cpp

@@ -1341,7 +1341,7 @@ void AP_GPS::calc_blended_state(void)
     state[GPS_BLENDED_INSTANCE].have_speed_accuracy = false;
     state[GPS_BLENDED_INSTANCE].have_horizontal_accuracy = false;
     state[GPS_BLENDED_INSTANCE].have_vertical_accuracy = false;
-    memset(&state[GPS_BLENDED_INSTANCE].location, 0, sizeof(state[GPS_BLENDED_INSTANCE].location));
+    state[GPS_BLENDED_INSTANCE].location = {};
 
     _blended_antenna_offset.zero();
     _blended_lag_sec = 0;

libraries/AP_GPS/AP_GPS.h

@@ -17,6 +17,7 @@
 #include <AP_HAL/AP_HAL.h>
 #include <inttypes.h>
 #include <AP_Common/AP_Common.h>
+#include <AP_Common/Location.h>
 #include <AP_Param/AP_Param.h>
 #include <AP_Math/AP_Math.h>
 #include <AP_Vehicle/AP_Vehicle.h>