P-Access-Network-Info ABNF Update

This document updates RFC 7315, by modifying the extension-access- info part of the P-Access-Network-Info header field Augmented Backus- Naur Form (ABNF), and by adding the following 'access-info' header field parameter values to the list of 'access-info' header field parameter values in the ABNF: 'operator-specific-GI' and 'utran-sai-3gpp'. The values are defined in the ABNF but are not included in the list.