UBI: fix some use after free bugs

Move the kmem_cache_free() calls down a couple lines.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/ubi/fastmap.c

@@ -463,8 +463,8 @@ static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
 				}
 			}
 			if (found_orphan) {
-				kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 				list_del(&tmp_aeb->u.list);
+				kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 			}
 
 			new_aeb = kmem_cache_alloc(ai->aeb_slab_cache,
@@ -846,16 +846,16 @@ fail_bad:
 	ret = UBI_BAD_FASTMAP;
 fail:
 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list) {
-		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 		list_del(&tmp_aeb->u.list);
+		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 	}
 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &eba_orphans, u.list) {
-		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 		list_del(&tmp_aeb->u.list);
+		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 	}
 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list) {
-		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 		list_del(&tmp_aeb->u.list);
+		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
 	}
 
 	return ret;