添加rtthread相关代码

riscv/rtthread/components/net/sal/include/dfs_net/dfs_net.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2015-02-17     Bernard      First version
+ * 2016-05-05     Bernard      rename dfs_lwip to dfs_net.
+ */
+
+#ifndef DFS_NET_H__
+#define DFS_NET_H__
+
+#include <dfs_file.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const struct dfs_file_ops* dfs_net_get_fops(void);
+int dfs_net_getsocket(int fd);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+