tpm: Support boot measurements

Add TPM2 functions to support boot measurement. This includes
starting up the TPM, initializing/appending the event log, and
measuring the U-Boot version. Much of the code was used in the
EFI subsystem, so remove it there and use the common functions.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
For the API moving around from EFI -> u-boot core
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
For EFI testing
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>