Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Add missing license header

    Change-Id: Ifd9015b50ef05040b8eb90a3ad3e3edddfd61811
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index dfc9aac..21a5c28 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit dfc9aacb02fe0e428bd82b39c5365183561909e4
+Subproject commit 21a5c285f7b91bb78e2ec225104cd46201547216