tpm_manager: support AUTHREAD/WRITE nvram spaces

tpm_manager used to always set POLICYREAD/WRITE for nvram spaces
it defined. That prevented utilities that use Tlcl (mount-encrypted)
from accessing such indexes, as Tlcl doesn't support policies.
Modify tpm_manager to use AUTHREAD/WRITE instead of POLICYREAD/WRITE
if no policy is specified.

BUG=chrome-os-partner:59973
TEST=Corp enroll, login, reboot, verify that still corp enrolled.
     Lockbox nvram space is readable using tpmc read.

Change-Id: Ieb3df0ad94879b25131f211954c09a5408982cce
Reviewed-on: https://chromium-review.googlesource.com/413018
Commit-Ready: Andrey Pronin <apronin@chromium.org>
Tested-by: Andrey Pronin <apronin@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
3 files changed