Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Merge "Cleanup `docs` folder"
  - Cleanup `docs` folder

    - move legacy document to `/legacy/docs`
    - move proposals to `docs/proposal`
    - remove unused `.gitkeep` files

    Change-Id: I1ad83ae98b7a6b3bb1738ced9b1f0d22c9c296b6
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index 4b58bc1..ebed515 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit 4b58bc19154552264af22e7f53099b0dee28845d
+Subproject commit ebed51569f56d240d26d060e7cf7d6c502b5545d