Update git submodules

* Update docs/submodules/sfc from branch 'stable/danube'
  - Fix missing argument in wait_for_classification_rules

    Change-Id: I4b41608ae7f91f51bd55d80c4e57b7e59e94855a
    Signed-off-by: Juan Vidal Allende <juan.vidal.allende@ericsson.com>

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index 54ac611..3c64135 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit 54ac61161108b037c1ccb3dca9cd2640f46b78b9
+Subproject commit 3c6413555fa3fd67676d1265b41e138e96f7decc