mkfs: simplify minimum log size calculation

mkfs: simplify minimum log size calculation

mkfs jumps through hoops to call libxfs_log_calc_minimum_size() to
set the minimum log size. We already have a xfs_mount at this point,
we just need to set the superblock up slightly earlier and then mkfs
can call libxfs_log_calc_minimum_size() directly. This means we can
remove mkfs/maxtrres.c completely.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>