db: support sparse inode chunk inobt record and sb fields

db: support sparse inode chunk inobt record and sb fields

The sparse inode feature uses a different on-disk inobt record format.
Define the new record format in the xfs_db type infrastructure and use
this definition for fs' that support sparse inodes.

Also update the superblock type structure with the sb_spino_align field.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>