Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Remove References to Securedlab"
  - Remove References to Securedlab

    PDF/IDFs have been moved out of securedlab to the Pharos repo. Any
    references to pulling the files from securedlab have been changed to
    look in pharos.

    Change-Id: I04608da51afdbe9ec55e3dd23c501c99946b58bb
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 6c4ec04..4dc7091 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 6c4ec042fc09cb0ee154aa64d69edb6c0c65a26b
+Subproject commit 4dc709177cdd7a78aa826c6764ea30a65a1c5b78