Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Bugfix: fix typo"
  - Bugfix: fix typo

    Change-Id: I9b7cd5f94b1663af3b807ce24c941868b10d85d1
    Signed-off-by: JingLu5 <lvjing5@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 2240fcc..d304708 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 2240fcc201fa9665e42e92c29e201cb62490acfa
+Subproject commit d304708efc188f4c7d5d52c1ecc1e0adf6d0dd45