f2fs: show more debug info for per-temperature log

- Add to account and show per-log dirty_seg, full_seg and valid_blocks
in debugfs.
- reformat printed info.

    TYPE            segno    secno   zoneno  dirty_seg   full_seg  valid_blk
  - COLD   data:     1523     1523     1523          1          0        399
  - WARM   data:      769      769      769         20        255     133098
  - HOT    data:      767      767      767          9          0        167
  - Dir   dnode:       22       22       22          3          0         70
  - File  dnode:      722      722      722         14         10       6505
  - Indir nodes:        2        2        2          1          0          3

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>