Update git submodules

Update git submodules

* Update docs/submodules/armband from branch 'stable/euphrates'
  - Makefile: Add `make upgrade` target

    1. Fix missing default `make` target for `all`

    2. `make submodules-clean` should checkout git submodule commit

       On patch apply, we tag the starting commit, so we can later export
       as patches all commits between that reference and another tag,
       applied simmetrically at the  end of the patch apply process.
       Previously, `submodules-clean` checked out that starting tag.
       Change that behavior to use the commit ID referenced by parent
       git repo (armband) submodule, so when armband git submodules are
       updated (e.g. sometimes `make upgrade` might include such changes),
       the new reference will be picked up automatically.

    3. Add `make upgrade` for fetching latest changes on current branch

    Change-Id: I03dc3953e91acfbe6ccb5e3bb2ccee7d28a0f7d5
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit 74238bffbde967b83a6c9db762caf8a18430dcd2)