xfs: remove XFS_DA_OP_INCOMPLETE

Now that we use the on-disk flags field also for the interface to the
lower level attr routines we can use the XFS_ATTR_INCOMPLETE definition
from the on-disk format directly instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>