bsc_api: Move BSC API between MSC and RSL code...

The lowlevel BSC paging API is a simple wrapper around
the RSL command. The BTS will automatically repeat these
messages but if we end up with two MSC inputs we will
need to count these messages somewhere...
diff --git a/openbsc/src/paging.c b/openbsc/src/paging.c
index 12ed903..ca37678 100644
--- a/openbsc/src/paging.c
+++ b/openbsc/src/paging.c
@@ -92,8 +92,7 @@
 		mi_len = gsm48_generate_mid_from_tmsi(mi, request->subscr->tmsi);
 
 	page_group = calculate_group(request->bts, request->subscr);
-	rsl_paging_cmd(request->bts, page_group, mi_len, mi,
-			request->chan_type);
+	gsm0808_page(request->bts, page_group, mi_len, mi, request->chan_type);
 }
 
 /*