Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "tg: speedup unittests, mock time.sleep"
  - tg: speedup unittests, mock time.sleep

    Change-Id: Ia6207c898653c3ba21b22e9c309e7abb25d5cd32
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 8cee055..2945003 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 8cee055d67f9d1e346361ab810dcfc24f0b9ccbc
+Subproject commit 2945003ca74fd3d73621c9e1745dd1662b88c2df