[BRIDGE]: Round off STP perodic timers.

Peroidic STP timers don't have to be exact.  The hold timer runs at
1HZ, and the hello timer normally runs at 2HZ; save power by aligning
it them to next second.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index 0e035d6..e38034a 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -178,7 +178,8 @@
 		br_send_config_bpdu(p, &bpdu);
 		p->topology_change_ack = 0;
 		p->config_pending = 0;
-		mod_timer(&p->hold_timer, jiffies + BR_HOLD_TIME);
+		mod_timer(&p->hold_timer,
+			  round_jiffies(jiffies + BR_HOLD_TIME));
 	}
 }