Add a reference to the shell for shell_surface

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/bin/e_comp_wl.h

@@ -369,6 +369,7 @@ struct _E_Wayland_Shell_Surface
 
    Eina_Bool active : 1;
 
+   void *shell;
    void *ping_timer;
 };