Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "add VNF scale-up template"
  - add VNF scale-up template

    adjust worker_threads based on number of vcpus

    Change-Id: Ie5444a64c15711a0e813905c69581f189432fe0b
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index c9db703..67ce9cc 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit c9db70332cd63fce03813c66e3c91e81112a9982
+Subproject commit 67ce9cc75d1bf2c11a6392a3ad2edfdba168ba91