Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Cleanup unittests for test_lmbench"
  - Cleanup unittests for test_lmbench

    unused-arg check was re-enabled after being disabled at a file level.
    Changes were made so that the file conforms to our testing conventions.

    Change-Id: Ie34a0088258c1aaff6cb0fdf0b86b37920d35bd6
    JIRA: YARDSTICK-1384
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ca7f539..e54efd1 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ca7f539f1071d925676273c14daf6137685a3d91
+Subproject commit e54efd1af4b07d508327db2cd3aa48e4473e1ba5