Remove dead code left over from NITB split

There still is a lot of dead code that we inherited from the NITB
days, let's remove more of it.

libtrau will be re-introduced as part of osmo-mgw later.

Change-Id: I8e0af56a158f25a4f1384d667c03eb20e72df5b8
diff --git a/include/osmocom/bsc/common_bsc.h b/include/osmocom/bsc/common_bsc.h
index 08394e9..32e5097 100644
--- a/include/osmocom/bsc/common_bsc.h
+++ b/include/osmocom/bsc/common_bsc.h
@@ -5,5 +5,4 @@
 
 struct gsm_network *bsc_network_init(void *ctx,
 				     uint16_t country_code,
-				     uint16_t network_code,
-				     mncc_recv_cb_t mncc_recv);
+				     uint16_t network_code);