RBS2000: Ensure the is-connection-list command is only used on RBS2000

... and not on other BTS models.

Change-Id: I8882ca9a9ab974b0bbdcbd5c3bab0eadf4bc0927
diff --git a/openbsc/src/libbsc/abis_om2000_vty.c b/openbsc/src/libbsc/abis_om2000_vty.c
index d48ff95..64d205c 100644
--- a/openbsc/src/libbsc/abis_om2000_vty.c
+++ b/openbsc/src/libbsc/abis_om2000_vty.c
@@ -348,6 +348,12 @@
 	uint8_t ci = atoi(argv[3]);
 	struct is_conn_group *grp, *grp2;
 
+	if (bts->type != GSM_BTS_TYPE_RBS2000) {
+		vty_out(vty, "%% IS MO only exists in RBS2000%s",
+			VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
 	if (!strcmp(argv[0], "add")) {
 		grp = talloc_zero(bts, struct is_conn_group);
 		grp->icp1 = icp1;