fsck.ubifs: rebuild_fs: Check and correct files' information

fsck.ubifs: rebuild_fs: Check and correct files' information

This is the 6/12 step of rebuilding. Correct the file information.
Traverse all files and calculate information (nlink, size, xattr_cnt,
etc.) for each file just like check_leaf() does, correct inode node
based on the calculated information.
Now, all files are consistent, and UBIFS will pass chk_fs after mounting.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>