extmod/modlwip: Change #ifdef to #if for check of MICROPY_PY_LWIP.
Otherwise this code will be included if MICROPY_PY_LWIP is defined to 0.
@@ -1500,7 +1500,7 @@ STATIC mp_obj_t lwip_print_pcbs() {
}
MP_DEFINE_CONST_FUN_OBJ_0(lwip_print_pcbs_obj, lwip_print_pcbs);
-#ifdef MICROPY_PY_LWIP
+#if MICROPY_PY_LWIP
STATIC const mp_rom_map_elem_t mp_module_lwip_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_lwip) },
