ESP8266: Add RTOS SDK port (MGOS_ESP8266_RTOS=1)

PUBLISHED_FROM=ca5332e63700274ed9aeea9d9d1802e89fa788fa

examples/ESP8266_RTOS/user/user_main.c

@@ -107,3 +107,7 @@ void user_init(void) {
   xTaskCreate(mg_task, (const signed char *) "mongoose", MG_TASK_STACK_SIZE,
               NULL, MGOS_TASK_PRIORITY, &s_mg_task_handle);
 }
+
+uint32_t user_rf_cal_sector_set(void) {
+  return 0xfb; /* 0xfb000, just before system data for 8Mbit flash. */
+}