Update git submodules

* Update docs/submodules/daisy from branch 'master'
  - md5sum check for cirros image

    Change-Id: I874c40eb5da54c38ce8aa2d1fb1840a8aee22b4c
    Signed-off-by: Zhijiang Hu <hu.zhijiang@zte.com.cn>

diff --git a/docs/submodules/daisy b/docs/submodules/daisy
index 6ea756e..31f3c22 160000 (submodule)
--- a/docs/submodules/daisy
+++ b/docs/submodules/daisy
@@ -1 +1 @@
-Subproject commit 6ea756e7cad324e70fd9546b15a268e910127d46
+Subproject commit 31f3c22980904fbdbe01c85be1c7d9d5f06b8c7f