[DFS] Remove stat/fstat function under WIN32 simulation.

components/dfs/src/dfs_posix.c

@@ -318,6 +318,7 @@ int unlink(const char *pathname)
 }
 RTM_EXPORT(unlink);
 
+#ifndef _WIN32 /* we can not implement these functions */
 /**
  * this function is a POSIX compliant version, which will get file information.
  *
@@ -382,6 +383,7 @@ int fstat(int fildes, struct stat *buf)
     return DFS_STATUS_OK;
 }
 RTM_EXPORT(fstat);
+#endif
 
 /**
  * this function is a POSIX compliant version, which shall request that all data