update sources to Ubuntu-6.8.0-23.23

(generated with debian/scripts/import-upstream-tag)

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/submodules/ubuntu-kernel b/submodules/ubuntu-kernel
index 4427c45609f6faf3b5b15e9e9246caa87894c36f..168e7b6ca98325ef7253b7112ed5b861c1bb519b 160000 (submodule)
--- a/submodules/ubuntu-kernel
+++ b/submodules/ubuntu-kernel
@@ -1 +1 @@
-Subproject commit 4427c45609f6faf3b5b15e9e9246caa87894c36f
+Subproject commit 168e7b6ca98325ef7253b7112ed5b861c1bb519b