[XFS] Sync up kernel and user-space headers

SGI-PV: 986558

SGI-Modid: xfs-linux-melb:xfs-kern:32231a

Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>