xfs: remove inode log format typedef

Remove xfs_inode_log_format_t now that xfs_inode_log_format is
explicitly padded and therefore is a real on-disk structure.  This
enables xfs/122 to check the size of the structure.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>