dm space map common: remove check for impossible sm_find_free() return value

The function sm_find_free() just returns -ENOSPC and 0.
So remove lone caller's check for some other error.
Signed-off-by: NZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

drivers/md/persistent-data/dm-space-map-common.c

@@ -369,10 +369,6 @@ int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
 			 */
 			dm_tm_unlock(ll->tm, blk);
 			continue;
-
-		} else if (r < 0) {
-			dm_tm_unlock(ll->tm, blk);
-			return r;
 		}
 
 		dm_tm_unlock(ll->tm, blk);