[w3c/webauthn] bd1c9b: Fix up TPM attestation format

  Branch: refs/heads/vgb-u2f-attestation
  Home:   https://github.com/w3c/webauthn
  Commit: bd1c9b116ff51d873e69392568208e0185c157e7
      https://github.com/w3c/webauthn/commit/bd1c9b116ff51d873e69392568208e0185c157e7
  Author: Vijay Bharadwaj <vijaybh@users.noreply.github.com>
  Date:   2017-01-10 (Tue, 10 Jan 2017)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Fix up TPM attestation format

Removed the TPM 1.2 parts.

Rounded out the section. Fixes #226.

Also clarified what certifyInfo contains. Fixes #242.