lchan: Every SS_LCHAN signal now sends a struct lchan_sig_data

The SS_LCHAN signals now always include the lchan_sig_data. For
the measurement report it will optionally include the measurement
report as well. Attempt to update all handlers of this signal as well
diff --git a/openbsc/src/handover_decision.c b/openbsc/src/handover_decision.c
index efafca6..4ac3286 100644
--- a/openbsc/src/handover_decision.c
+++ b/openbsc/src/handover_decision.c
@@ -277,15 +277,15 @@
 static int ho_dec_sig_cb(unsigned int subsys, unsigned int signal,
 			   void *handler_data, void *signal_data)
 {
-	struct gsm_meas_rep *mr;
+	struct lchan_signal_data *lchan_data;
 
 	if (subsys != SS_LCHAN)
 		return 0;
 
+	lchan_data = signal_data;
 	switch (signal) {
 	case S_LCHAN_MEAS_REP:
-		mr = signal_data;
-		process_meas_rep(mr);
+		process_meas_rep(lchan_data->mr);
 		break;
 	}