Convert tbf->control_ts to be a gprs_rlcmac_pdch*

This allows having full information on the control TS easily reachable
(like TRX ofthe PDCH), and makes it easy to compare TS by simply
matching the pointer address.

Change-Id: I6a97b6528b2f9d78dfbca8fb97ab7c621f777fc7
---
M src/pcu_vty_functions.cpp
M src/pdch.cpp
M src/tbf.cpp
M src/tbf.h
M tests/alloc/AllocTest.cpp
M tests/alloc/AllocTest.err
M tests/alloc/AllocTest.ok
M tests/tbf/TbfTest.cpp
M tests/tbf/TbfTest.err
M tests/types/TypesTest.err
10 files changed, 51,486 insertions(+), 51,491 deletions(-)