CR50: use vendor template for RSA endorsement primary keygen
CR50: use vendor template for RSA endorsement primary keygen

When generating the RSA endorsement primary key, use the
CR50 vendor specific template.  Doing so generates the
RSA key corresponding to the certificate issued at manufacture.

Also, always start the RSA key generation counter at 1.  Doing
so matches the certificate generation process at manufacture;
and there is no harm in always starting at 1, since the key
generation process remains deterministic.

BUG=none
BRANCH=none
TESTED=generated key matches endorsement cert;
  checked via attestation_client

Change-Id: I6a5c329e99292e32f880c0c5ea364d511cb6ea82
Signed-off-by: nagendra modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Reviewed-on: https://chromium-review.googlesource.com/386279
Commit-Ready: Nagendra Modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Tested-by: Nagendra Modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Tested-by: Andrey Pronin <53bbebe6910b11f7aa2d1daaa466658eb4cba5f2@chromium.org>
Reviewed-by: Bill Richardson <129945214b1d548d8e49b6c29c43094f8c78057f@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec