Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Improve IXIA TG Rx/TX throughput calculation"
  - Improve IXIA TG Rx/TX throughput calculation

    Use float instead of integer to convert TG throughtput
    IXIA statistic.

    JIRA: YARDSTICK-1378

    Change-Id: I39bd143adc4b10035c6f0986a06d407a18aa0887
    Signed-off-by: Mytnyk, Volodymyr <volodymyrx.mytnyk@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index eb9e5be..2752112 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit eb9e5bea682f610383cf238820c8044ae66f2a3e
+Subproject commit 27521123b2a178ce5d9038a4901e65ced0b9e35e