Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Do NOT hardcode interface speed for PROX tests

    JIRA: YARDSTICK-1035

    Do not hardcode NIC/interface speed in PROX test. Test assumes
    NIC used is 10Gbps. This is incorrect. It could support 1Gbps,
    10Gbps, 25Gbps, 40Gbps or something else.

    This is used to calculate pps (Packets Per Second)
    In Baremetal the NIC speed could be extracted. however when
    run on a virtual machine this is not possible.

    Solution:
    Add in options section of test file.

    eg.
    Options:
      interface_speed_gbps: 10

    Where 10 refers to a 10Gbps. In a setup where multiple interfaces
    are used. This will refer to the speed of the slowest connection.

    Change-Id: I89ab16479a2cdd1d79e52cbcc5a972762c60d057
    Signed-off-by: Daniel Martin Buckley <daniel.m.buckley@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index f753fb8..f7e4771 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit f753fb86cc26e08dca168c0827d28a7b6f022d1f
+Subproject commit f7e477133cfc87134bb860aaaf39d932bbae1907