Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Refine documentation"
  - Refine documentation

    Change-Id: I0d3387a520e3decf51bb0f7db53996f148a611d0
    Signed-off-by: JingLu5 <lvjing5@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ab7cd79..f782757 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ab7cd795f6d45bf8bedbe8903cae39bd447d3c19
+Subproject commit f782757a1af7bddbcb2af9cebc33d4668ebb24f5