Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Adding intel_pmu tools plugin for collectd"
  - Adding intel_pmu tools plugin for collectd

    Change-Id: I81ff3d43d209e98188855c8b2eb302835bb5d417
    Signed-off-by: Neha Vadnere <neha.r.vadnere@intel.com>
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 58b399d..22dfb4f 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 58b399dee7bdff055ca8cfb712d1e0c753d2f58c
+Subproject commit 22dfb4fcb474ac201a22c5b3ce3c34baec641f9d