Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - Merge "Fix Malformed Table in User Guide docs" into stable/euphrates
  - Fix Malformed Table in User Guide docs

    Change-Id: I2f98b75e9bbcd3d0cd4666c097a3280dd89eb02a
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>
    (cherry picked from commit 74c2176823913f09821ea2671c9008e5c74954b8)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index e973003..269c070 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit e9730038f1bc4c2f781518faf3a7335ad58d0441
+Subproject commit 269c070a51389914c87b8f2c66a199ecabb6c5bb