Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Provide average latency results in IXIA KPIs"
  - Provide average latency results in IXIA KPIs

    IXIA KPIs will provide an average value of all port latency values:
    max, min and avg.

    JIRA: YARDSTICK-1394

    Change-Id: Ib7c7b5300e8343a1af0a20cb4e49c0bd669c1143
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index c6175b5..057652b 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit c6175b5bc59706c3a423fe2781f99e32930bb570
+Subproject commit 057652b25f68dd4720dbc40e7919237d3888fb12