tpm: add TPMBackendCmd to hold the request state

This simplifies a bit locality handling, and argument passing, and
could pave the way to queuing requests (if that makes sense).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
6 files changed