Update git submodules

* Update docs/submodules/ipv6 from branch 'stable/fraser'
  - Updated Release Notes for Fraser 6.1.0

    Change-Id: Ifaef0ee50ce047c43685b25e1cc00a18b30b646d
    Signed-off-by: Bin Hu <bh526r@att.com>
    (cherry picked from commit b0bacdee18cbe308b3a218be86ed548a2ec65d3f)

diff --git a/docs/submodules/ipv6 b/docs/submodules/ipv6
index 5b91469..b8d475e 160000 (submodule)
--- a/docs/submodules/ipv6
+++ b/docs/submodules/ipv6
@@ -1 +1 @@
-Subproject commit 5b914695088b39aee3886bd60be4707b7a11a1e8
+Subproject commit b8d475e1bae1ef46aa9207cb306cc4b51276f032