selftests/bpf: Consolidate VIRTIO/9P configs in config.vm file

selftests/bpf: Consolidate VIRTIO/9P configs in config.vm file

Those configs are needed to be able to run VM somewhat consistently.
For instance, ATM, s390x is missing the `CONFIG_VIRTIO_CONSOLE` which
prevents s390x kernels built in CI to leverage qemu-guest-agent.

By moving them to `config,vm`, we should have selftest kernels which are
equal in term of VM functionalities when they include this file.

The set of config unabled were picked using

    grep -h -E '(_9P|_VIRTIO)' config.x86_64 config | sort | uniq

added to `config.vm` and then
    grep -vE '(_9P|_VIRTIO)' config.{x86_64,aarch64,s390x}

as a side-effect, some config may have disappeared to the aarch64 and
s390x kernels, but they should not be needed. CI will tell.

Signed-off-by: Manu Bretelle <chantr4@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231031212717.4037892-1-chantr4@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>