Introduce init() APIs for PDCH and TRX objects

This will make it easier to keep object specific initializations in
expected place.

Change-Id: Idf1dbdf8bc0b1e16d86eeeffb1193fdf3a57d6ef
diff --git a/src/bts.h b/src/bts.h
index 15a72bd..3ddf501 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -65,6 +65,7 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
+void bts_trx_init(struct gprs_rlcmac_trx *trx, struct gprs_rlcmac_bts *bts, uint8_t trx_no);
 void bts_trx_reserve_slots(struct gprs_rlcmac_trx *trx, enum gprs_rlcmac_tbf_direction dir, uint8_t slots);
 void bts_trx_unreserve_slots(struct gprs_rlcmac_trx *trx, enum gprs_rlcmac_tbf_direction dir, uint8_t slots);
 void bts_trx_free_all_tbf(struct gprs_rlcmac_trx *trx);