silent_call: Add option to choose channel type

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/openbsc/src/silent_call.c b/openbsc/src/silent_call.c
index 2679db7..a0c166e 100644
--- a/openbsc/src/silent_call.c
+++ b/openbsc/src/silent_call.c
@@ -113,11 +113,11 @@
 
 
 /* initiate a silent call with a given subscriber */
-int gsm_silent_call_start(struct gsm_subscriber *subscr, void *data)
+int gsm_silent_call_start(struct gsm_subscriber *subscr, void *data, int type)
 {
 	int rc;
 
-	rc = paging_request(subscr->net, subscr, RSL_CHANNEED_TCH_F,
+	rc = paging_request(subscr->net, subscr, type,
 			    paging_cb_silent, data);
 	return rc;
 }