xfs: introduce new v5 bulkstat structure

xfs: introduce new v5 bulkstat structure

Source kernel commit: 7035f9724f8497c709077c08df2073bfcde9c2f5

Introduce a new version of the in-core bulkstat structure that supports
our new v5 format features.  This structure also fills the gaps in the
previous structure.  We leave wiring up the ioctls for the next patch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>