AP_SmartRTL: increase default pts to 300

libraries/AP_SmartRTL/AP_SmartRTL.h

@@ -10,7 +10,7 @@
 
 // definitions and macros
 #define SMARTRTL_ACCURACY_DEFAULT        2.0f   // default _ACCURACY parameter value.  Points will be no closer than this distance (in meters) together.
-#define SMARTRTL_POINTS_DEFAULT          150    // default _POINTS parameter value.  High numbers improve path pruning but use more memory and CPU for cleanup. Memory used will be 20bytes * this number.
+#define SMARTRTL_POINTS_DEFAULT          300    // default _POINTS parameter value.  High numbers improve path pruning but use more memory and CPU for cleanup. Memory used will be 20bytes * this number.
 #define SMARTRTL_POINTS_MAX              500    // the absolute maximum number of points this library can support.
 #define SMARTRTL_TIMEOUT                 15000  // the time in milliseconds with no points saved to the path (for whatever reason), before SmartRTL is disabled for the flight
 #define SMARTRTL_CLEANUP_POINT_TRIGGER   50     // simplification will trigger when this many points are added to the path