tss2: Implement grub_tcg2_cap_pcr() for EFI

tss2: Implement grub_tcg2_cap_pcr() for EFI

This commit implements grub_tcg2_cap_pcr() for EFI by using the UEFI
TCG2 protocol, HashLogExtendEvent, to extend the specified PCR with an
EV_SEPARATOR event and ensure the event will be recorded properly in the
TPM event log.

Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>