Update git submodules

* Update docs/submodules/barometer from branch 'master'
  - Merge "dpdk stats: add known issues/limitations"
  - dpdk stats: add known issues/limitations

    Change-Id: I8dbd43002f50e65df40cc8bfb516c40f995b9679
    Signed-off-by: Mytnyk, Volodymyr <volodymyrx.mytnyk@intel.com>

diff --git a/docs/submodules/barometer b/docs/submodules/barometer
index f88957c..a6c9c4e 160000 (submodule)
--- a/docs/submodules/barometer
+++ b/docs/submodules/barometer
@@ -1 +1 @@
-Subproject commit f88957cc68ef57f872f502e3d6fa462f2222dc1b
+Subproject commit a6c9c4e51d5035a4583ea08f7673d49b667025ae