tpm: Enable boot despite unknown firmware failure
Currently booting the system is prevented when call to EFI firmware
hash_log_extend_event() returns unknown error. Solve this by following
convention used in commit
a4356538d (commands/tpm: Don't propagate
measurement failures to the verifiers layer).
Let the system to be bootable by default when unknown TPM error is
encountered. Check environment variable tpm_fail_fatal to fallback to
previous behaviour.
Signed-off-by: Michał Grzelak <mchl.grzlk@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>