fix dfsv2 romfs dfs_romfs_getdents buffer overflow.

components/dfs/dfs_v2/filesystems/romfs/dfs_romfs.c

@@ -352,7 +352,7 @@ static int dfs_romfs_getdents(struct dfs_file *file, struct dirent *dirp, uint32
 
         d->d_namlen = rt_strlen(name);
         d->d_reclen = (rt_uint16_t)sizeof(struct dirent);
-        rt_strncpy(d->d_name, name, rt_strlen(name) + 1);
+        rt_strncpy(d->d_name, name, DFS_PATH_MAX);
 
         /* move to next position */
         ++ file->fpos;