Only use the default Xbox mapping on Linux

On Windows, this is already covered by XInput and is the wrong mapping if we try to use it with DirectInput/RAWINPUT/WGI controllers

src/joystick/SDL_gamecontroller.c

@@ -1161,15 +1161,12 @@ static ControllerMapping_t *SDL_PrivateGetControllerMappingForNameAndGUID(const
             mapping = SDL_PrivateAddMappingForGUID(guid,
 "none,X360 Wireless Controller,a:b0,b:b1,back:b6,dpdown:b14,dpleft:b11,dpright:b12,dpup:b13,guide:b8,leftshoulder:b4,leftstick:b9,lefttrigger:a2,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b10,righttrigger:a5,rightx:a3,righty:a4,start:b7,x:b2,y:b3",
                           &existing, SDL_CONTROLLER_MAPPING_PRIORITY_DEFAULT);
+        } else if (SDL_strstr(name, "Xbox") || SDL_strstr(name, "X-Box") || SDL_strstr(name, "XBOX")) {
+            mapping = s_pXInputMapping;
         }
     }
 #endif /* __LINUX__ */
 
-    if (!mapping && name && !SDL_IsJoystickWGI(guid)) {
-        if (SDL_strstr(name, "Xbox") || SDL_strstr(name, "X-Box") || SDL_strstr(name, "XBOX")) {
-            mapping = s_pXInputMapping;
-        }
-    }
     if (!mapping) {
         mapping = s_pDefaultMapping;
     }