Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - Merge "NSB TRex: convert DPDK port number to logical TRex port number" into stable/euphrates
  - NSB TRex: convert DPDK port number to logical TRex port number

    when we create TRex config we sort based on PCI bus address
    and create a logical port ordering.

    We need to save this port ordering and re-use it everywhere.

    redirect vnfd_helper.port_num() to resource_helper.port_num() to
    use the logical mapping

    Change-Id: Ibff628556d5e11e686e15716a66a3210758c4ff0
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>
    (cherry picked from commit ce52059f5f78912eeff2d97235c1028c218bf960)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 7504787..f21e473 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 7504787fe62ad20e4237624440911bcde77b4393
+Subproject commit f21e47326025eb8e9d45170a93d7ec43128c1f77