Update git submodules

Update git submodules

* Update docs/submodules/fuel from branch 'stable/fraser'
  - Merge "maas: boot-resources: Dynamic arch list from PDF" into stable/fraser
  - maas: boot-resources: Dynamic arch list from PDF

    Instead of leaving MaaS default to 'amd64', explicitly set the list
    of architectures to support based on PDF data.

    Change-Id: I852a3ce156db3df0c090f10c0b45c26058dbb6c6
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit be45e3157fe19b8905e3a30f7f839a728a6c6df7)