WIP: rlcmac: Rearrange csn1 related definitions

This patch contains several changes trying to isolate and enclose all
the CSN1 data structure big amount of churn, to avoid annoying readers
not interested in that part of the code (most of the time).

* osmo_gprs_rlcmac_encode/decode* APIs are kept private (gprs_rlmac_*)
* Related tests now link againt .a instead of .la to access the private
  symbols.
* All CSN1 content is split into 2 parts:
** csn1_defs: Contain the data types and definitions used by the CSN1
   encoder/decoder
** csn1_encdec: Contain the functions and related code calling the CSN1
   encoder/decoder

Hence, gprs_rlcmac.h is split into csn1_defs.h and csn1_encdec.h, and
most of the content of ts_*.c is moved to csn1_defs_ts_*.c and
csn1_encdec_ts_*.c.
Only CSN1-agnostic content (like enums and value_strings) are kept in
ts_*.c files, and defined in types.h.

TODO: lots of CSN_DESCR need to have its "static" removed and
CSN_DESCR_EXTERN() added to csn1_defs.h or csn1_encdec.h.

Change-Id: I7f48c1f40581c7689b280c0881d88c4900d56a10
---
M debian/copyright
M include/osmocom/gprs/rlcmac/Makefile.am
R include/osmocom/gprs/rlcmac/csn1_defs.h
A include/osmocom/gprs/rlcmac/csn1_encdec.h
M include/osmocom/gprs/rlcmac/rlcmac_enc.h
M include/osmocom/gprs/rlcmac/types.h
M src/rlcmac/Makefile.am
R src/rlcmac/csn1_defs_ts_24_008.c
R src/rlcmac/csn1_defs_ts_44_018.c
A src/rlcmac/csn1_defs_ts_44_060.c
A src/rlcmac/csn1_encdec_ts_24_008.c
A src/rlcmac/csn1_encdec_ts_44_018.c
A src/rlcmac/csn1_encdec_ts_44_060.c
M src/rlcmac/rlcmac_enc.c
M src/rlcmac/tbf_ul.c
M src/rlcmac/tbf_ul_ass_fsm.c
M src/rlcmac/ts_44_060.c
M tests/rlcmac/Makefile.am
M tests/rlcmac/ts_44_018_test.c
M tests/rlcmac/ts_44_018_test.ok
M tests/rlcmac/ts_44_060_test.c
M tests/rlcmac/ts_44_060_test.ok
22 files changed, 5,572 insertions(+), 5,412 deletions(-)