wayland_egl: Fix rendering on systems without buffer age

If buffer age isn't present we really want to return MODE_FULL, but we were
previously returning MODE_AUTO.

On recent mali drivers this resulted in accidental partial updates leading
to incorrect rendering.

src/modules/evas/engines/wayland_egl/evas_wl_main.c

@@ -388,6 +388,7 @@ eng_outbuf_swap_mode_get(Outbuf *ob)
         return swap_mode;
      }
 
+   if (ob->swap_mode == MODE_AUTO) return MODE_FULL;
    return ob->swap_mode;
 }