Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Enable multi-port perf in trex as TG

    set TRex -c option for threads per port based on
    hardware number of queues.

    We can't auto-detect number of queues and we can't
    use more than one thread per core on systems with single-queue
    interfaces, so move the option to the config file

    options:
      tg_0:
        queues_per_port: 2

    also enable trex debug by removing >/dev/null redirection

    options:
      tg_0:
        trex_server_debug: true

    Change-Id: I46da187849282bf28f4ef5b333e1ae890e202768
    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 dd3cbc2..cec4342 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit dd3cbc21dfb505ea70dd3574869c1fb33b7de956
+Subproject commit cec4342dee5c13260b680f6dddbc33ae5bf0c127