xfs: simplify setting bio flags

Stop using the deprecated bio_set_op_attrs helper, and use a single
argument to xfs_buf_ioapply_map for the operation and flags.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>