WinRT: minor code cleanup in window-creation code

Window flags can be detected on all WinRT platforms.

src/video/winrt/SDL_winrtvideo.cpp

@@ -529,20 +529,10 @@ WINRT_CreateWindow(_THIS, SDL_Window * window)
     }
 #endif
 
-#if SDL_WINRT_USE_APPLICATIONVIEW
     /* Determine as many flags dynamically, as possible. */
     window->flags =
         SDL_WINDOW_BORDERLESS |
         SDL_WINDOW_RESIZABLE;
-#else
-    /* Set SDL_Window flags for Windows Phone 8.0 */
-    window->flags =
-        SDL_WINDOW_FULLSCREEN_DESKTOP |
-        SDL_WINDOW_BORDERLESS |
-        SDL_WINDOW_MAXIMIZED |
-        SDL_WINDOW_INPUT_GRABBED |
-        SDL_WINDOW_RESIZABLE;
-#endif
 
 #if SDL_VIDEO_OPENGL_EGL
     if (data->egl_surface) {