docs: add new ext4 superblock time extension fields

The superblock timestamp fields were enlarged by u8 to be 40 bits wide.
Update the documentation to reflect this.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2018-07-29 16:16:21 -04:00 • committed by Theodore Ts'o
commit f5cb282d8b