Update comments about ISO spec on aac parser.

Previously comments on aac_parser did not specify
which edition of ISO 14496-3 it refered.

This patch is to update the comments to clearly specify
that current implementation refers ISO 14496-3:2005.

BUG=532281

Review URL: https://codereview.chromium.org/1421293009

Cr-Commit-Position: refs/heads/master@{#359027}
2 files changed