xfs: move xfs_attr_defer_type up in xfs_attr_item.c

We'll reference it directly in xlog_recover_attri_commit_pass2, so move
it up a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>