Update git submodules

* Update docs/submodules/compass4nfv from branch 'master'
  - Merge "build: add docker-ce apt repo for aarch64"
  - build: add docker-ce apt repo for aarch64

    Change-Id: I5b3c30e6202c4db45d02221d3e4b7e7250b1fd01
    Signed-off-by: Yibo Cai <yibo.cai@arm.com>

diff --git a/docs/submodules/compass4nfv b/docs/submodules/compass4nfv
index c0fb7bb..9c15a37 160000 (submodule)
--- a/docs/submodules/compass4nfv
+++ b/docs/submodules/compass4nfv
@@ -1 +1 @@
-Subproject commit c0fb7bb71a92988f4c1504690cb9c3ee1870378b
+Subproject commit 9c15a3763f01c60879b0ce49094952f2fb941add