Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Add --hwlb options as a command line argument for SampleVNF"
  - Add --hwlb options as a command line argument for SampleVNF

    To enable HWLB queues in samplevnf on supported hardware
    (e.g Intel  Fortville) --hwlb option needs to be passed
    as a VNF command line argument.

    JIRA: YARDSTICK-1159

    Change-Id: I6e5c098dc71a711252b545c7622ee52085fa81f0
    Signed-off-by: Chornyi, TarasX <tarasx.chornyi@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 74db27b..789a6e6 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 74db27b3fc0447cceda2f60e3bf05420d5bad8b9
+Subproject commit 789a6e66d0c2f6fe2244ddd00b9841635756e00f