sim/framebuffer: fix memory leak

LeakSanitizer: detected memory leaks in XStringListToTextProperty

Signed-off-by: yanxiaowei <yanxiaowei@xiaomi.com>

arch/sim/src/sim/posix/sim_x11framebuffer.c

@@ -106,6 +106,8 @@ static inline Display *sim_x11createframe(void)
 
   XSetWMProperties(display, g_window, &winprop, &iconprop, argv, 1,
                    &hints, NULL, NULL);
+  XFree(winprop.value);
+  XFree(iconprop.value);
 
   /* Select window input events */