libbsc: Create the RF interface all the time

The interface can be accessed through CTRL and a socket. But currently
it is only available when the socket interface has been configured.
Create the interface all the time but only listen on the socket when
a path has been specified.
diff --git a/openbsc/src/osmo-nitb/bsc_hack.c b/openbsc/src/osmo-nitb/bsc_hack.c
index 0183934..96ae0b8 100644
--- a/openbsc/src/osmo-nitb/bsc_hack.c
+++ b/openbsc/src/osmo-nitb/bsc_hack.c
@@ -293,12 +293,10 @@
 	/* seed the PRNG */
 	srand(time(NULL));
 
-	if (rf_ctrl_name) {
-		rf_ctrl = osmo_bsc_rf_create(rf_ctrl_name, bsc_gsmnet);
-		if (!rf_ctrl) {
-			fprintf(stderr, "Failed to create the RF service.\n");
-			exit(1);
-		}
+	rf_ctrl = osmo_bsc_rf_create(rf_ctrl_name, bsc_gsmnet);
+	if (!rf_ctrl) {
+		fprintf(stderr, "Failed to create the RF service.\n");
+		exit(1);
 	}
 
 	if (db_init(database_name)) {