esp8266/main: Init recently added dupterm_arr_obj port state var.

esp8266/main.c

@@ -57,6 +57,7 @@ STATIC void mp_reset(void) {
     #endif
     MP_STATE_PORT(mp_kbd_exception) = mp_obj_new_exception(&mp_type_KeyboardInterrupt);
     MP_STATE_PORT(term_obj) = MP_OBJ_NULL;
+    MP_STATE_PORT(dupterm_arr_obj) = MP_OBJ_NULL;
     pin_init0();
     readline_init0();
 #if MICROPY_MODULE_FROZEN