Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "sriov: Determine path to the bind-tool"
  - sriov: Determine path to the bind-tool

    In case of SRIOV path to the bind-tool must be known before
    NIC driver is re-initialized. It means before TestCase.__init__()
    is called.

    Change-Id: Ib6fdba233e665144510dd492462c0a21aa19ed71
    Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
    Reviewed-by: Al Morton <acmorton@att.com>
    Reviewed-by: Christian Trautman <ctrautma@redhat.com>
    Reviewed-by: Sridhar Rao <sridhar.rao@spirent.com>
    Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>

diff --git a/docs/submodules/vswitchperf b/docs/submodules/vswitchperf
index 8a1b74a..6583def 160000 (submodule)
--- a/docs/submodules/vswitchperf
+++ b/docs/submodules/vswitchperf
@@ -1 +1 @@
-Subproject commit 8a1b74a4fdbafdef256cec64501f1ec751f03b9f
+Subproject commit 6583defcc0c5610f296c33446d5521d9030fc2b8