f2fs-tools: add option to display directory tree

This option shows directory tree of f2fs.

Usage: fsck.f2fs -t /dev/sdx

`-- p0
   |-- f4
   `-- d6
        |-- f5e
        |-- cb6
        |-- fdb
        |-- fe8
        `-- l9a

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
4 files changed