firewire: unnecessary BM delay after generation rollover

Noticed by Jarod Wilson:  The bus manager work was unnecessarily delayed
each time the bus generation counter rolled over.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
diff --git a/drivers/firewire/fw-topology.c b/drivers/firewire/fw-topology.c
index e7520e4..8dd6703 100644
--- a/drivers/firewire/fw-topology.c
+++ b/drivers/firewire/fw-topology.c
@@ -523,7 +523,7 @@
 	 * previously processed one, we cannot reliably compare the
 	 * old and new topologies.
 	 */
-	if ((generation & 0xff) != ((card->generation + 1) & 0xff) &&
+	if (!is_next_generation(generation, card->generation) &&
 	    card->local_node != NULL) {
 		fw_notify("skipped bus generations, destroying all nodes\n");
 		fw_destroy_nodes(card);