Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Removed zero from tc number

    Originally tc number was TC0042, after fix TC042.

    Change-Id: I3c36e39a141ec8eb74f9f00d7218bd511a56fbc9
    Signed-off-by: Mika Rautakumpu <mika.rautakumpu@nokia.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 35ca724..b4a9e14 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 35ca724899b3e0a8c58af6323dc4622736ee0625
+Subproject commit b4a9e140274023a1451f6b409352e33442d0c2d4