tcgbios: Add TPM 2.0 support and firmware API

This patch adds TPM 2.0 support along with the firmware API that Linux
uses to transfer the firmware log.

The firmware API follows the "PFW Virtual TPM Driver" specification.
The API has callers in existing Linux code (prom_init.c) from TPM 1.2
times but the API also works for TPM 2.0 without modifications.

The TPM 2.0 support logs PCR extensions of measurements of code and data.
For this part we follow the TCG specification "TCG PC Client
Platform Firmware Profile Specification" (section "Event Logging").

Other relevant specs for the construction of TPM commands are:
- Trusted Platform Module Library; Part 2 Structures
- Trusted Platform Module Library; Part 3 Commands

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
[aik: removed new blank lines at EOF]
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>