dm-crypt: don't update io->sector after kcryptd_crypt_write_io_submit()

dm-crypt: don't update io->sector after kcryptd_crypt_write_io_submit()

The updates of io->sector are the leftovers when dm-crypt allocated
pages for partial write request. However, since commit cf2f1abfbd0db
("dm crypt: don't allocate pages for a partial request"), there is no
partial request anymore.

After the introduction of write request rb-tree, the updates of
io->sectors may interfere the insertion procedure, because ->sectors of
these write requests which have already been added in the rb-tree may be
changed during the insertion of new write request.

Fix it by removing these buggy updates of io->sectors. Considering these
updates only effect the write request rb-tree, the commit which
introduces the write request rb-tree is used as the fix tag.

Fixes: b3c5fd305249 ("dm crypt: sort writes")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>