Update git submodules

* Update docs/submodules/armband from branch 'stable/euphrates'
  - AArch64 NIC adaptation patch

    AArch64 NIC adaptation for dual NIC boards with traffic separation
     -kvm nodes: added second trunk_nic
     -compute nodes: removed third external_nic

    Change-Id: I874094075ab01c7fe21af26602a7366a371cec28
    Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>
    (cherry picked from commit e7260544c63bfd1e52a52839ad6527b0bc2ce75d)

diff --git a/docs/submodules/armband b/docs/submodules/armband
index 773df73..956d1d0 160000 (submodule)
--- a/docs/submodules/armband
+++ b/docs/submodules/armband
@@ -1 +1 @@
-Subproject commit 773df7376cf7eb15e78d1e029bdfc0220634484f
+Subproject commit 956d1d0056c54fe4c886126dcf489b547b01d49a