cfq-iosched: log responsible 'cfqq' in idle timer arm

Makes it easier to read the traces.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 579f318..090a4ee 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -936,7 +936,7 @@
 		sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
 
 	mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
-	cfq_log(cfqd, "arm_idle: %lu", sl);
+	cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
 }
 
 /*