Modify EGPRS DL TBF flow to support SPB

Modify the EGPRS DL TBF flow to support Split block during
Retx. This patch will also Upgrade the test suite with test cases
to validate the EGPRS Downlink SPB for Retransmission

Scenarios like MCS6->MCS3, MCS4->MCS1, MCS5->MCS2, MCS9->MCS3
MCS7->MCS2, MCS8->MCS3 have been simulated and Integration tested
in NuRAN 1.0 hardware thoroughly.

Change-Id: I242afdd8ae7622dec8593b26382ad66bad5b9516
diff --git a/src/tbf.h b/src/tbf.h
index 1bd7878..2a1bfe8 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -421,6 +421,11 @@
 	int analyse_errors(char *show_rbb, uint8_t ssn, ana_result *res);
 	void schedule_next_frame();
 
+	enum egprs_rlc_dl_reseg_bsn_state egprs_dl_get_data
+		(int bsn, uint8_t **block_data);
+	unsigned int get_egprs_dl_spb_status(int bsn);
+	enum egprs_rlcmac_dl_spb get_egprs_dl_spb(int bsn);
+
 	struct osmo_timer_list m_llc_timer;
 };