update submodule to 8.5.1 tag

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

diff --git a/frr b/frr
index 79188bf710e92acf42fb5b9b0a2e9593a5ee9b05..7a2b85ae52b354248fa9da04100efba0ec6c70c9 160000 (submodule)
--- a/frr
+++ b/frr
@@ -1 +1 @@
-Subproject commit 79188bf710e92acf42fb5b9b0a2e9593a5ee9b05
+Subproject commit 7a2b85ae52b354248fa9da04100efba0ec6c70c9