on_each_cpu(): kill unused 'retry' parameter

It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.

Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

mm/slub.c

@@ -1497,7 +1497,7 @@ static void flush_cpu_slab(void *d)
 static void flush_all(struct kmem_cache *s)
 {
 #ifdef CONFIG_SMP
-	on_each_cpu(flush_cpu_slab, s, 1, 1);
+	on_each_cpu(flush_cpu_slab, s, 1);
 #else
 	unsigned long flags;