Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Refactor to make file sys more like class inheritance"
  - Refactor to make file sys more like class inheritance

    Change-Id: I5471d2e894ca78407a57f3ba01202264c69ad174
    Signed-off-by: Edward MacGillivray <edward.s.macgillivray@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 5d35ee7..4de16cb 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 5d35ee70c26bb5d3a4ce150b874982966360db11
+Subproject commit 4de16cbc3c7a4e03542c6256f3aeda79dbf49b62