Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'stable/danube'
  - Merge "Adapt lmbench scripts for aarch64 nodes" into stable/danube
  - Adapt lmbench scripts for aarch64 nodes

    LMBench shell scripts were invoking x86_64 executables.
    This made them fail when executed on aarch64 nodes.
    Added architecture detection and proper command call.

    JIRA: ARMBAND-268

    Change-Id: I8c9e87158631f7f5479adc2fda9558f9f7e54406
    Signed-off-by: Alexandru Nemes <alexandru.nemes@enea.com>
    (cherry picked from commit fd2b3173d21d34720f714e7e6358dafe7d1ada12)