Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - remove apexlake-verify

    Change-Id: I5ac8e5d573c390460e2472c7b3b4649cc78dd295
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 36375f3..4cd3529 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 36375f388880519336328406de1d1bbc408d4599
+Subproject commit 4cd35297332c1fbfa114ff8b237ee3d4864f7498