Update error output to include all possible values

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5477 43c1dc8c-776e-4df2-8ef1-6e829299be21
Change str output from dtmfmode enum

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5478 43c1dc8c-776e-4df2-8ef1-6e829299be21
Used the new TYPE_ENUM sccp_config_parser to parse dtmfmode using a generic parsing instead of a dedicated one (reducing the possibility of outdated parsers when sccp_config_entries or _enum.hh files change).

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5479 43c1dc8c-776e-4df2-8ef1-6e829299be21