qemu: Update query-cpu-model-expansion check
qemu: Update query-cpu-model-expansion check

CPU features are available on ARM only wherever the
query-cpu-model-expansion QMP command is available, same as
on s390. Update qemuBuildCpuModelArgStr() to reflect this
fact.

Signed-off-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>
Tested-by: Andrew Jones <20ca6a98b2289e315ee985b8cb9cb36522e95d55@redhat.com>
Reviewed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

zippy2/libvirt,zippy2/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,zippy2/libvirt,olafhering/libvirt,crobinso/libvirt,zippy2/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,nertpinx/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,crobinso/libvirt,jfehlig/libvirt,nertpinx/libvirt,libvirt/libvirt,fabianfreyer/libvirt,libvirt/libvirt,libvirt/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,olafhering/libvirt,jardasgit/libvirt,olafhering/libvirt,jfehlig/libvirt,crobinso/libvirt,fabianfreyer/libvirt,olafhering/libvirt,crobinso/libvirt,jfehlig/libvirt,nertpinx/libvirt