generalize channel activation / channel mode modify

* we only need one piece of code to calculate rsl_ie_chan_mode from
  our run-time data structures (gsm_lchan)
* add some more channel modes for TCH/H and data
* use enum's to make the compiler warn us about unhandled enum values
* make sure the caller determines the (signalling,speech,data) mode
5 files changed
tree: 7ca65b8eaa226d2f25b26ae465aa497138d8be83
  1. linux-kernel/
  2. openbsc/
  3. wireshark/