[Openid-specs-mobile-profile] Issue #191: IANA registration for CIBA errors (openid/mobile)

[josephheenan]

New issue 191: IANA registration for CIBA errors
https://bitbucket.org/openid/mobile/issues/191/iana-registration-for-ciba-errors

Joseph Heenan:

I think `invalid_user_code`, `authorization_pending`, etc need to be added to the IANA Considerations section to register them to [https://www.iana.org/assignments/oauth-parameters/oauth-parameters.xhtml#extensions-error](https://www.iana.org/assignments/oauth-parameters/oauth-parameters.xhtml#extensions-error) ?