mkfs.xfs(8): remove incorrect default inode allocator description

mkfs.xfs(8): remove incorrect default inode allocator description

The "maxpct" section of the mkfs.xfs manpage has a gratuitous and
incorrect description of the default inode allocator mode.

inode64 has been the default since 2012, as of

08bf540412ed xfs: make inode64 as the default allocation mode

so the description is wrong. In addition, imaxpct is only
tangentially related to inode allocator behavior, so this section
of the man page is really the wrong place for discussion.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>