xfs: constify xfs_item_ops

The log item ops aren't nessecarily the biggest exploit vector, but marking
them const is easy enough.  Also remove the unused xfs_item_ops_t typedef
while we're at it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>

fs/xfs/xfs_dquot_item.c

@@ -295,7 +295,7 @@ xfs_qm_dquot_logitem_committing(
 /*
  * This is the ops vector for dquots
  */
-static struct xfs_item_ops xfs_dquot_item_ops = {
+static const struct xfs_item_ops xfs_dquot_item_ops = {
 	.iop_size	= xfs_qm_dquot_logitem_size,
 	.iop_format	= xfs_qm_dquot_logitem_format,
 	.iop_pin	= xfs_qm_dquot_logitem_pin,
@@ -483,7 +483,7 @@ xfs_qm_qoff_logitem_committing(
 {
 }
 
-static struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
+static const struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
 	.iop_size	= xfs_qm_qoff_logitem_size,
 	.iop_format	= xfs_qm_qoff_logitem_format,
 	.iop_pin	= xfs_qm_qoff_logitem_pin,
@@ -498,7 +498,7 @@ static struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
 /*
  * This is the ops vector shared by all quotaoff-start log items.
  */
-static struct xfs_item_ops xfs_qm_qoff_logitem_ops = {
+static const struct xfs_item_ops xfs_qm_qoff_logitem_ops = {
 	.iop_size	= xfs_qm_qoff_logitem_size,
 	.iop_format	= xfs_qm_qoff_logitem_format,
 	.iop_pin	= xfs_qm_qoff_logitem_pin,