Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "task: initialize result"
  - task: initialize result

    Change-Id: I8d6b9bed24c9afa4be54296515e6aa91e84fe650
    Signed-off-by: Martin Banszel <martinx.banszel@intel.com>
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 631162a..88a06c6 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 631162a347f8bc5f25b04729c29e4948f77b2622
+Subproject commit 88a06c612e3321c3e8773c0791396b391a867e6c