Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - [release] Yardstick Fraser 6.0.0 Release notes

    JIRA: YARDSTICK-1129

    Change-Id: I5adb2e9547c58b90d3eafb0e2b90015ce5472cfa
    Signed-off-by: rexlee8776 <limingjiang@huawei.com>
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 14094f7..a324c1b 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 14094f7bf478224d5631494d1fa41bf9e8ba2cde
+Subproject commit a324c1b922ae2598dbe25e9b2885620ef09f4901