dm crypt: fix error return code in crypt_ctr()

Fix to return error code -ENOMEM from the mempool_create_kmalloc_pool()
error handling case instead of 0, as done elsewhere in this function.

Fixes: ef43aa38 ("dm crypt: add cryptographic data integrity protection (authenticated encryption)")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-crypt.c

@@ -2746,6 +2746,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 			cc->tag_pool_max_sectors * cc->on_disk_tag_size);
 		if (!cc->tag_pool) {
 			ti->error = "Cannot allocate integrity tags mempool";
+			ret = -ENOMEM;
 			goto bad;
 		}