[paging] Keep a copy of the Control Channel Description in the bts struct

- Initialize Control Channel Description of SI3 
- Patch the table
- Setting ATT now is easy
- Paging can now extract all required information... to determine
  the right paging group.

tree: 5984ab62e5fcb3cccd4d68655f6d8377f139fe91
  1. tests/
  2. tools/
  3. AUTHORS
  4. configure.in
  5. COPYING
  6. Makefile.am
  7. README