Changed data structures for TBF and PDCH instances, to allow multislot

The new data structure is required to define slot/TFI assigment for MS
with multislot capability.

Now there are two lists for TBFs: uplink and downlink. It is possible to
have different TBFs with same TFI in the same direction, as long as they
are assigned on different timeslots.

See tbf.txt for description.

Note: This does not implement any multislot support. It defines the new
data structure. Currently only the first slot is assigned.
diff --git a/src/sysmo_sock.cpp b/src/sysmo_sock.cpp
index 390f3f6..6b390ed 100644
--- a/src/sysmo_sock.cpp
+++ b/src/sysmo_sock.cpp
@@ -97,7 +97,10 @@
 		for (ts = 0; ts < 8; ts++) {
 			bts->trx[trx].pdch[ts].enable = 0;
 			for (tfi = 0; tfi < 32; tfi++) {
-				tbf = bts->trx[trx].pdch[ts].tbf[tfi];
+				tbf = bts->trx[trx].pdch[ts].ul_tbf[tfi];
+				if (tbf)
+					tbf_free(tbf);
+				tbf = bts->trx[trx].pdch[ts].dl_tbf[tfi];
 				if (tbf)
 					tbf_free(tbf);
 			}