Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - private-> uplink and public->downlink

    changing private and public to new uplink/downlink name

    Change-Id: I8c3f582ba5592418a397e2500e0b998c3eed54f2
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 4967785..19e0c4d 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 49677852f2bc690d235318d2208504241eef61a9
+Subproject commit 19e0c4d2e004e18e6f5687e420dc51a4032b06c2