qemu: tpm: do not update profile name for transient domains

qemu: tpm: do not update profile name for transient domains

If we do not have a persistent definition, there's no point in
looking for it since we cannot store it.

Also skip the update if the tpm device(s) in the persistent
definition are different.

This fixes the crash when starting a transient domain.

https://issues.redhat.com/browse/RHEL-69774
https://gitlab.com/libvirt/libvirt/-/issues/715

Fixes: d79542eec669eb9c449bb8228179e7a87e768017
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>