tpm: ibmvtpm: Add support for TPM2

Support TPM2 in the IBM vTPM driver. The hypervisor tells us what
version of TPM is connected through the vio_device_id.

In case a TPM2 device is found, we set the TPM_CHIP_FLAG_TPM2 flag
and get the command codes attributes table. The driver does
not need the timeouts and durations, though.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>