tests: Add TPM coverage to default-models tests

tests: Add TPM coverage to default-models tests

We have a non-trivial amount of architecture-specific logic
dealing with TPM, so it's good to have coverage for it.

Note that two architectures currently don't have support for
TPM devices enabled by default in QEMU: loongarch64 and s390x.
The situation might change for the former, but that's unlikely
to happen for the latter.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>