Document where to find the how to determine the paging group

Point to the right location in the pile of spec
diff --git a/src/abis_rsl.c b/src/abis_rsl.c
index f5e1577..ab22ed2 100644
--- a/src/abis_rsl.c
+++ b/src/abis_rsl.c
@@ -400,14 +400,6 @@
 	return 0;
 }
 
-# if 0
-int rsl_paging_cmd_imsi(struct gsm_bts *bts, u_int8_t chan_needed, const char *imsi_str)
-{
-	/* FIXME: derive the MS Identity */
-	return rsl_paging_cmd(bts, paging_group, x, y, chan_needed);
-}
-#endif
-
 /* Chapter 8.5.6 */
 int rsl_imm_assign_cmd(struct gsm_bts *bts, u_int8_t len, u_int8_t *val)
 {
diff --git a/src/bsc_hack.c b/src/bsc_hack.c
index dba7933..9fa0157 100644
--- a/src/bsc_hack.c
+++ b/src/bsc_hack.c
@@ -827,6 +827,7 @@
 		return;
 	}
 
+	/* FIXME: 05.02  6.5.2 Determination of CCCH_GROUP and PAGING_GROUP... */
 	/* get the station to page */
 	pending_station = (struct pending_registered_station*) pending_stations.next;
 	mi_len = generate_mid_from_tmsi(mi, pending_station->tmsi);