Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "BugFIX: NSB-setup build script fix for BM"
  - BugFIX: NSB-setup build script fix for BM

    JIRA: YARDSTICK-994

    The NSB set-up script for baremetal is broken.
    In nsb_setp.yml file, "Prepare baremetal machine"
    is commented due to which the ubuntu_server_baremetal_deploy_samplevnfs.yml
    file is never called.

    Change-Id: Icc95018ba746d6efa5baf09322b3255806da8952
    Signed-off-by: Abhijit Sinha <abhijit.sinha@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 92f982f..6c50522 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 92f982f27f64247a1ad5c74fcf7800db294f7dd5
+Subproject commit 6c5052211e1e3f82d55946d2df090ad787382494