Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - docs: Remove whitespaces from indexes

    Whitespaces were removed from RST indexes to correctly
    pass rst validation.

    Change-Id: I5f277d5f8846653c6e7ea3fbb29881e2dd3f610b
    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 22faa4f..e64800b 160000 (submodule)
--- a/docs/submodules/vswitchperf
+++ b/docs/submodules/vswitchperf
@@ -1 +1 @@
-Subproject commit 22faa4f0a15caf61065ff1fa5033e3da72a79680
+Subproject commit e64800b3cf4cbfd89996cb56f1899b047f6cbdbc