gsm0408: Adding log output for 3g specific RR messages

GSM 04.18, which is the successor of GSM 04.08, describes
additional RR 3g specific message types. This commit adds
log output for those messages. The behaviour is not changed
all affected message types are still forwared to the MSC
as they were before.

See also 3GPP TS 04.18, section 10.4, table 10.4.1

The change requires to update libosmocore as well, see
also commit f48fdb3a108da0dc23d7af4ac021e98e11f07152 in
libosmocore.git for details.

Change-Id: I41f2242fdf59c3eb4b3f8f7f003c17f7e0df01aa
diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c
index a22e3c2..3e362fa 100644
--- a/openbsc/src/libmsc/gsm_04_08.c
+++ b/openbsc/src/libmsc/gsm_04_08.c
@@ -1270,8 +1270,8 @@
 		rc = gsm48_rx_rr_app_info(conn, msg);
 		break;
 	default:
-		LOGP(DRR, LOGL_NOTICE, "MSC: Unimplemented "
-			"GSM 04.08 RR msg type 0x%02x\n", gh->msg_type);
+		LOGP(DRR, LOGL_NOTICE, "MSC: Unimplemented %s GSM 04.08 RR "
+		     "message\n", gsm48_rr_msg_name(gh->msg_type));
 		break;
 	}