Add USDD code from Mike Haben

This is the initial checkin of the USSD code from Mike Haben.  I didn't
put it in the main branch as I think it still needs some cleanup.
6 files changed
tree: 0d923eca102bd5bdffa9d8c78ddb9c21398374cf
  1. hlrsync/
  2. linux-kernel/
  3. openbsc/
  4. wireshark/