Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "[docs] Remove the VTC chapter in the userguide"
  - [docs] Remove the VTC chapter in the userguide

    Other references to VTC have also been removed.

    Change-Id: Ia5592e29ddca1bf05cefa5b1364e0757ac78bc79
    JIRA: YARDSTICK-1335
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 7e33865..f32d9e5 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 7e33865cfa9f9306d2735fb4573cde1fa22d6862
+Subproject commit f32d9e5e452429905c8099db9b5d4a0fa14dff13