Merge pull request #4670 from mysterywolf/network

[network][lwip][kconfig] 默认LWIP协议栈版本由2.0.2转为2.1.2

components/net/Kconfig

@@ -114,7 +114,7 @@ config RT_USING_LWIP
     if RT_USING_LWIP
         choice
             prompt "lwIP version"
-            default RT_USING_LWIP202
+            default RT_USING_LWIP212
             help
                 Select the lwIP version