Changes

TRAU frame output EDATA: set sync pattern bits

osmo_trau_frame_encode() for OSMO_TRAU16_FT_EDATA previously failed
to set the sync pattern bits in the generated output.  Fix it.

Change-Id: Iacd391cb6d389d8320c8ed767878eed144ee9d69

trau_frame: D145_SYNC does not follow EDATA format

14.5 kbit/s data service uses a special protocol: the CCU and the
TRAU exchange D145_SYNC frames first, conveying only alignment of
320-bit TRAU frames, then switch to EDATA frames that can carry
payload.  (EDATA frames don't have enough sync pattern bits to be
reliable against false alignment.)

Per TS 48.060 section 5.5.3, D145_SYNC frames are structured like
"regular" (lower rates) data frames with all payload bits set to 1,
_not_ like EDATA frames.  Therefore:

* osmo_trau_frame_decode_16k() should decode D145_SYNC frames like
  regular data frames, not like EDATA;

* osmo_trau_frame_encode() given OSMO_TRAU16_FT_D145_SYNC should
  produce a frame with correct sync pattern and all-1 payload bits,
  but with control bits up to C15 per TS 48.060 section 5.5.3.

Change-Id: I7c743996fc620227438225ffda419217881034d1

trau2rtp: add support for EDATA

Regular DATA frames are used for 9.6 kbit/s and lower data services,
EDATA frames are used for 14.4 kbit/s service.  Add support for
the latter.

Change-Id: If5344eb4718ac95b996e20caf969de35a9c8a35d

rtp2trau: add support for EDATA

Change-Id: I538567ac208c89b3fc8f4dc408dc15a813a1272a