with xfs_iflush() gone, we can rename xfs_iflush_int() back to
xfs_iflush(). Also move it up above xfs_iflush_cluster() so we don't
need the forward definition any more.
Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>