xfs: use internal dfops in attr code

xfs: use internal dfops in attr code

Source kernel commit: 9c6bb0cf7ba318767107328f39aac880344ddd2e

Remove the unnecessary on-stack dfops structure and use the internal
transaction dfops instead. The lower level xattr code already
appropriately accesses ->t_dfops throughout.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>