Changes

jobs/{gerrit,master,update-osmo-ci}: add aarch64 case

The newly set up rpi4-raspbian11build-ansible-1 returns aarch64 for
arch (it has an aarch64 OS instead of 32-bit arm like the others
currently have). Add "aarch64" to the cases next to arm*, so these work
as expected again.

Related: OS#6549
Change-Id: Iaf987d05870d842cd297f5f14c8542bf75835414

jobs/{master,gerrit}: rpi4-raspbian11 -> raspbian

Rename the jenkins label rpi4-raspbian11 to raspbian so the name is not
misleading with how we currently use it. One raspberry pi has been
reinstalled with raspbian12 (OS#6549) and we also use it for LX2 with a
raspbian container (OS#5873, therefore remove rpi4 from the name).

The OS running directly on the rpi / in the LXC is not that important
anyway since we run the actual jobs in docker with the latest debian
version (currently 12).

Change-Id: I02dcf3098ffd3fa247c4f43c290d6e3fd809ad45

jobs/update-osmo-ci-on-slaves: update rpi4-1 name

As it runs raspbian 12 now, adjust the name.

Change-Id: I863bf95d06f91a2cb377070b6aefef30d9e30d51

jobs/{gerrit,master}: aarch64: use setarch linux32

Pretend to be a 32 bit arm machine when running the arm jobs, so in
combination with the related commit we can build test for 32 bit arm
on rpi4s with a 64 bit raspberry pi OS.

Related: docker-playground I93986569a9f492237da28fbc534ac5ccd176f120
Change-Id: Ib082daac0c896787440a58e1aa21f3bb775e4975

Stop building openbsc

With recent changes in libosmo-sccp, openbsc does not build anymore.
The openbsc.git repo has been unmaintained/unsupported for 7 years, so
let's finally remove related build jobs instead of fixing this.

Related: libosmo-sccp I299a32a2f8f61477cf49c8126567fef2092d5407
Change-Id: Ie58f54c3f2a224fb1e3a0c95bd3ed85e7859fdc9