Refactor and clarify tbf->triger_ass() code

Split the function into 2 functions, one for assignment on PACCH and one
for assignment on PCH. This makes code calling this API far more clearer
on what is the exact aim when assigning the TBF.

Change-Id: Ic92867e55337b0bd6b5bfc97f13b7982eedb1cb7
diff --git a/src/tbf_dl.h b/src/tbf_dl.h
index e0daf57..ba5d582 100644
--- a/src/tbf_dl.h
+++ b/src/tbf_dl.h
@@ -41,7 +41,6 @@
 
 	int rcvd_dl_ack(bool final_ack, unsigned first_bsn, struct bitvec *rbb);
 	struct msgb *create_dl_acked_block(uint32_t fn, uint8_t ts, enum mcs_kind req_mcs_kind = EGPRS);
-	void trigger_ass(struct gprs_rlcmac_tbf *old_tbf);
 
 	void request_dl_ack();
 	bool need_poll_for_dl_ack_nack() const;
@@ -138,7 +137,8 @@
 		  const uint8_t egprs_ms_class, const uint16_t delay_csec,
 		  const uint8_t *data, const uint16_t len);
 
-void tbf_dl_trigger_ass(struct gprs_rlcmac_dl_tbf *tbf, struct gprs_rlcmac_tbf *old_tbf);
+void dl_tbf_trigger_ass_on_pacch(struct gprs_rlcmac_dl_tbf *tbf, struct gprs_rlcmac_tbf *old_tbf);
+void dl_tbf_trigger_ass_on_pch(struct gprs_rlcmac_dl_tbf *tbf);
 void tbf_dl_request_dl_ack(struct gprs_rlcmac_dl_tbf *tbf);
 
 static inline struct gprs_rlcmac_tbf *dl_tbf_as_tbf(struct gprs_rlcmac_dl_tbf *dl_tbf)