dm: fix double RCU unlock in dm_dax_zero_page_range() error path

Remove redundant dm_put_live_table() in dm_dax_zero_page_range() error
path to fix sparse warning:
drivers/md/dm.c:1208:9: warning: context imbalance in 'dm_dax_zero_page_range' - unexpected unlock

Fixes: cdf6cdc ("dm,dax: Add dax zero_page_range operation")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Author: snitm

drivers/md/dm.c

@@ -1201,11 +1201,9 @@ static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 		 * ->zero_page_range() is mandatory dax operation. If we are
 		 *  here, something is wrong.
 		 */
-		dm_put_live_table(md, srcu_idx);
 		goto out;
 	}
 	ret = ti->type->dax_zero_page_range(ti, pgoff, nr_pages);
-
  out:
 	dm_put_live_table(md, srcu_idx);