update sources to Ubuntu-5.4.0-38.42

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

diff --git a/submodules/ubuntu-focal b/submodules/ubuntu-focal
index 14b92656279b8f52054edda356167e0eef92dc8d..51ee04d9d3b464e9aa8509013779491f0b001ebc 160000 (submodule)
--- a/submodules/ubuntu-focal
+++ b/submodules/ubuntu-focal
@@ -1 +1 @@
-Subproject commit 14b92656279b8f52054edda356167e0eef92dc8d
+Subproject commit 51ee04d9d3b464e9aa8509013779491f0b001ebc