Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Bugfix in role enable_hugepages_on_boot"
  - Bugfix in role enable_hugepages_on_boot

    Make role idempotent.
    Current regex doesn't match for:
    linux   /boot/vmlinuz-4.10.0-30-generic root=/dev/nvme0n1p1 ro vga=788 text

    Change-Id: If5eb20fce4ddc35bb109c00eb7565853b3763950
    Signed-off-by: Jan Malanik <janx.malanik@intel.com>
    Signed-off-by: Malanik Jan <janx.malanik@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 9bef739..d93f0b4 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 9bef739e89f3b230c9e0a53c2286a440017ec948
+Subproject commit d93f0b4e79bcf822dfb264a82e879f45038628d1