xfs: set up inode operation vectors later

In the next patch we'll set up different inode operations for inline vs
out of line symlinks, for that we need to make sure the flags are already
set up properly.

[dchinner: added xfs_setup_iops() call to xfs_rename_alloc_whiteout()]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>