TBF: add helpers for assignment type handling

* add function to set/unset given assignment type
* log assignment type flag changes
* update tests output with additional logs

This enables us to carefully track the TBF assignment type transitions.

Change-Id: I3fe9d52472be8b7f257e8326b2f84e8e7d7bd1f4
Related: OS#1759
diff --git a/src/bts.cpp b/src/bts.cpp
index 72e1621..3d29ad6 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -759,7 +759,7 @@
 		} else {
 			tbf->set_ta(ta);
 			TBF_SET_STATE(tbf, GPRS_RLCMAC_FLOW);
-			tbf->state_flags |= (1 << GPRS_RLCMAC_FLAG_CCCH);
+			TBF_ASS_TYPE_SET(tbf, GPRS_RLCMAC_FLAG_CCCH);
 			T_START(tbf, T3169, m_bts.t3169, 0, "RACH (new UL-TBF)", true);
 			LOGPTBF(tbf, LOGL_DEBUG, "[UPLINK] START\n");
 			LOGPTBF(tbf, LOGL_DEBUG, "RX: [PCU <- BTS] RACH "
@@ -1042,7 +1042,7 @@
 			LOGPTBF(new_tbf, LOGL_INFO,
 				"The TBF has been confirmed on the PACCH, "
 				"changed type from CCCH to PACCH\n");
-			new_tbf->state_flags |= (1 << GPRS_RLCMAC_FLAG_PACCH);
+			TBF_ASS_TYPE_SET(new_tbf, GPRS_RLCMAC_FLAG_PACCH);
 		}
 		TBF_SET_STATE(new_tbf, GPRS_RLCMAC_FLOW);
 		/* stop pending assignment timer */