Update git submodules

* Update docs/submodules/nfvbench from branch 'master'
  - [NFVBENCH-58] Add option to specify dest MAC with EXT CHAIN when ARP is
    disabled

    Change-Id: Ia605d7314d8047e84c5e17088ed5ce588a50e256
    Signed-off-by: Michael Pedersen <michael.soelvkaer@gmail.com>

diff --git a/docs/submodules/nfvbench b/docs/submodules/nfvbench
index 02c8ed9..5a7cb16 160000 (submodule)
--- a/docs/submodules/nfvbench
+++ b/docs/submodules/nfvbench
@@ -1 +1 @@
-Subproject commit 02c8ed97e27b6e417945d27d4d3c2ab8e7dbfa7e
+Subproject commit 5a7cb16e9b178ee70b29a554fcbd6f582a1f031a