TPM: workaround to enforce PCR updates across suspends

Add a workaround for TPM's which fail to flush last written
PCR values in a TPM_SaveState, in preparation for suspend.

Signed-off-by: David Safford <safford@watson.ibm.com>
Acked-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>