update zfs submodule to 2.2.6

patches did not need adaptation

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>

diff --git a/upstream b/upstream
index 2566592045780e7be7afc899c2496b1ae3af4f4d..baa50314567afd986a00838f0fa65fdacbd12daf 160000 (submodule)
--- a/upstream
+++ b/upstream
@@ -1 +1 @@
-Subproject commit 2566592045780e7be7afc899c2496b1ae3af4f4d
+Subproject commit baa50314567afd986a00838f0fa65fdacbd12daf