[VCP VMs] AArch64: Switch seeding back to qemu-nbd

[VCP VMs] AArch64: Switch seeding back to qemu-nbd

Upstream change [1] switched from old qemu-nbd preseeding of VCP VMs
to using a cloud-init + configuration drive. This breaks on AArch64
with "IDE controllers are unsupported for this QEMU binary or machine
type", so switch back to using qemu-nbd.

[1] https://github.com/Mirantis/reclass-system-salt-model/commit/c0e4807

Change-Id: I0dfeb638d408343c76a73fafa503048a79ce1f6e
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
(cherry picked from commit f4f2820028953e970f1216846be25079cdadcd24)