Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "docs: Fix typo in SRIOV docs"
  - docs: Fix typo in SRIOV docs

    Details about SRIOV kernel settings were accidentally interrupted
    by VPP related note.

    JIRA: VSPERF-198

    Change-Id: Id9d5ed39d62fbe16cf2e4f4aa730f5d15845b727
    Signed-off-by: Martin Klozik <martin.klozik@tieto.com>
    Reviewed-by: Al Morton <acmorton@att.com>
    Reviewed-by: Christian Trautman <ctrautma@redhat.com>
    Reviewed-by: Sridhar Rao <sridhar.rao@spirent.com>