bsc_api: Add needed parameters to the assignment complete callback

Provide the chosen channel and more information in the assignment
complete method.
diff --git a/openbsc/src/bsc/osmo_bsc_api.c b/openbsc/src/bsc/osmo_bsc_api.c
index 5570241..f22e9a7 100644
--- a/openbsc/src/bsc/osmo_bsc_api.c
+++ b/openbsc/src/bsc/osmo_bsc_api.c
@@ -39,7 +39,9 @@
 {
 }
 
-static void bsc_assign_compl(struct gsm_subscriber_connection *conn, uint8_t rr_cause)
+static void bsc_assign_compl(struct gsm_subscriber_connection *conn, uint8_t rr_cause,
+			     uint8_t chosen_channel, uint8_t encr_alg_id,
+			     uint8_t speech_model)
 {
 }