Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Setup tempest_smoke images for arm64

    Configure the images to be used for tempest_smoke
    testcase for ARM

    JIRA: ARMBAND-395

    Change-Id: Ia13507d70fd05ef541a5154886d52fa388731cee
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 51b476d..61881e3 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 51b476da479b32ece3cee36dccd75191e0832940
+Subproject commit 61881e3926165a10657d02ebe627636cf6a61ecc