upstream: update to 3.1.7

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

diff --git a/upstream b/upstream
index 23db6cba49b6bca811e5d08091e000e260649ee5..91348f865938e56108b04927818be7ea05b58285 160000 (submodule)
--- a/upstream
+++ b/upstream
@@ -1 +1 @@
-Subproject commit 23db6cba49b6bca811e5d08091e000e260649ee5
+Subproject commit 91348f865938e56108b04927818be7ea05b58285