tpm: sandbox: Update for needed TPM2 capabilities

The driver needs to support getting the PCRs in the capabilities
command. Fix various other things and support the max number
of PCRs for TPM2.
Remove the !SANDBOX dependency for EFI TCG2 as well.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>