AP_GPS: fix SBP supported status

libraries/AP_GPS/AP_GPS_SBP.cpp

@@ -282,10 +282,10 @@ AP_GPS_SBP::_attempt_state_update()
 
         if (pos_llh->flags == 0)
             state.status = AP_GPS::GPS_OK_FIX_3D;
-        else if (pos_llh->flags == 2)
-            state.status = AP_GPS::GPS_OK_FIX_3D_DGPS;
         else if (pos_llh->flags == 1)
             state.status = AP_GPS::GPS_OK_FIX_3D_RTK_FLOAT;
+        else if (pos_llh->flags == 2)
+            state.status = AP_GPS::GPS_OK_FIX_3D_RTK_FIXED;
         
 
         last_full_update_tow = last_vel_ned.tow;

libraries/AP_GPS/AP_GPS_SBP.h

@@ -29,7 +29,7 @@ class AP_GPS_SBP : public AP_GPS_Backend
 public:
     AP_GPS_SBP(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UARTDriver *_port);
 
-    AP_GPS::GPS_Status highest_supported_status(void) { return AP_GPS::GPS_OK_FIX_3D_RTK_FLOAT; }
+    AP_GPS::GPS_Status highest_supported_status(void) { return AP_GPS::GPS_OK_FIX_3D_RTK_FIXED; }
 
     // Methods
     bool read();