Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Adjusted IPs in some prox tests.

    Change-Id: Iff39fa5b90d1ae5534ce1fff31dfb84c1e47340c
    Signed-off-by: Maciej Skrocki <maciej.skrocki@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 12722dc..9cefa93 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 12722dca61e657942182b236ca0281aabee47b96
+Subproject commit 9cefa935afa908cede3ab1bd8b6ca91f1e36ad2d