Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 6ffddbea33bb13caa0a43aa9f22086ffbac0f9fd
  - Generate all Functest jobs via XtestingCI

    Change-Id: I62813002c7160c6df19efc24f842a35b00fc9b20
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit 8bca3cbe2507c70920d6224504063bfb160588c8)

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 5441456..6ffddbe 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 54414563c2b8d41d37a18d597fe62bd2f567f3ac
+Subproject commit 6ffddbea33bb13caa0a43aa9f22086ffbac0f9fd