Update git submodules

* Update docs/submodules/clover from branch 'master'
  - Simplification of Clover Fraser official docs

    (Double commit from master:I89adbef74aa74071a055dcdf62aa0925e263ffe3,
    gerrit 56167)

    Change-Id: I86f12d5ba67f09177eca758c184c614ee9d6dd9d
    Signed-off-by: Stephen Wong <stephen.kf.wong@gmail.com>

diff --git a/docs/submodules/clover b/docs/submodules/clover
index 3f36f39..a52bd21 160000 (submodule)
--- a/docs/submodules/clover
+++ b/docs/submodules/clover
@@ -1 +1 @@
-Subproject commit 3f36f3957c131a24642591f9d16870dddd3d32e2
+Subproject commit a52bd21da0ee6206ddd61347bc9052d78155a916